enVision Math Common Core Grade 2 Answer Key Topic 4 Fluently Add Within 100

enVision Math Common Core 2nd Grade Answers Key Topic 4 Fluently Add Within 100

Essential Question:
What are strategies for adding numbers to 100?
Envision Math Common Core 2nd Grade Answer Key Topic 4 Fluently Add Within 100 1

enVision STEM Project: Making and Using Models
Find Out Find and share books about Hawaii and volcanoes. Make a model of a volcano that becomes an island. Tell about how the island can change over a long time.
Journal: Make a Book Show what you learn in a book. In your book, also:

  • Draw pictures to show how volcanoes can become islands.
  • Show how you can use models to help you add numbers to 100.

Review What You Know

Vocabulary
Question 1.
Circle the tens digit in each number.
73
53
82
Answer:
The tens digit in each number is 7,5 and 8.

Explanation:
Given that the digits are 73, 53, 82. So the tens digit in each number is 7,5 and 8.

Question 2.
Circle the ones digit in each number.
34
43
97
Answer:
The ones digit in each number is 4,3 and 7.

Explanation:
Given that the digits are 73, 53, 82. So the one digit in each number is 4,3 and 7.

Question 3.
Break apart 23 into tens and ones.
23 = _________ tens and ______ ones
Answer:
23 = 2 tens and 3 ones.

Explanation:
Given that the number is 23, so after a break apart of 23 it will be 2 tens and 3 ones.

Mental Math
Question 4.
Use mental math to find each sum.
34 + 10 = _________
50 + 5 = _________
20 + 40 = _________
Answer:
44, 55, 60.

Explanation:
The sum of
34 + 10 = 44
50 + 5 = 55
20 + 40 = 60.

Open Number Line
Question 5. Use the open number line to find 39 + 15.
Envision Math Common Core 2nd Grade Answer Key Topic 4 Fluently Add Within 100 2
39 + 15 = _________
Answer:

Math Story
Question 6.
Stacy has 17 marbles. Diana gives her 22 marbles. How many marbles does Stacy have now?
______ marbles
Answer:
The number of marbles does Stacy has now is 39 marbles.

Explanation:
Given that Stacy has 17 marbles and Diana gives her 22 marbles. So the number of marbles does Stacy has now is 17 + 22 which is 39 marbles.

Pick a Project

PROJECT 4A
Where can you bike near home?
Project: Make a Bike Trail Brochure
Envision Math Common Core 2nd Grade Answer Key Topic 4 Fluently Add Within 100 3

PROJECT 4B
What kinds of coral grow in Florida?
Project: Build a Coral Model
Envision Math Common Core 2nd Grade Answer Key Topic 4 Fluently Add Within 100 4

PROJECT 4C
What do you collect?
Project: Display a Rock and Leaf Collection
Envision Math Common Core 2nd Grade Answer Key Topic 4 Fluently Add Within 100 5

PROJECT 4D
How much does it cost to visit the Kennedy Space Center?
Project: Make a Space Center Poster
Envision Math Common Core 2nd Grade Answer Key Topic 4 Fluently Add Within 100 6

Lesson 4.1 Add 2-Digit Numbers Using Models

Solve & Share
Leslie collects 36 rocks. Her brother collects 27 rocks. How many rocks do they collect in all? Use place-value blocks to help you solve. Show your place-value blocks.
I can … use models to add 2-digit numbers and then explain my work.
Envision Math Common Core 2nd Grade Answer Key Topic 4 Fluently Add Within 100 7

Visual Learning Bridge
Envision Math Common Core 2nd Grade Answer Key Topic 4 Fluently Add Within 100 8

Convince Me! When do you need to regroup when adding?

Guided Practice

Add. Use place-value blocks to find each sum. Regroup if needed.
Question 1.
32 + 29 = ________
Envision Math Common Core 2nd Grade Answer Key Topic 4 Fluently Add Within 100 9
_______ tens ______ ones
Answer:
6 tens and 1 ones.

Explanation:
Given that the sum of 32 + 29 is 61. So there are 6 tens and 1 one.

Question 2.
24 + 52 = _______
Envision Math Common Core 2nd Grade Answer Key Topic 4 Fluently Add Within 100 10
_______ tens ______ ones
Answer:
7 tens and 6 ones.

Explanation:
Given that the sum of 24 + 52 is 76. So there are 7 tens and 6 ones.

Question 3.
15 + 38 = _______
Envision Math Common Core 2nd Grade Answer Key Topic 4 Fluently Add Within 100 11
_______ tens ______ ones
Answer:
5 tens and 3 ones.

Explanation:
Given that the sum of 15 + 38 is 53. So there are 5 tens and 3 ones.

Independent Practice

Add. Use place-value blocks to find each sum. Regroup if needed.
Question 4.
36 + 29 = _______
Answer:
6 tens and 5 ones.

Explanation:
Given that the sum of 36 + 29 is 65. So there are 6 tens and 5 ones.

Question 5.
27 + 23 = _______
Answer:
5 tens and 0 ones.

Explanation:
Given that the sum of 27 + 23 is 50. So there are 5 tens and 0 ones.

Question 6.
59 + 13 = _______
Answer:
7 tens and 2 ones.

Explanation:
Given that the sum of 59 + 13 is 72. So there are 7 tens and 2 ones.

Question 7.
24 + 35 = _______
Answer:
5 tens and 9 ones.

Explanation:
Given that the sum of 24 + 35 is 59. So there are 5 tens and 9 ones.

Question 8.
58 + 25 = _______
Answer:
8 tens and 3 ones.

Explanation:
Given that the sum of 58 + 25 is 83. So there are 8 tens and 3 ones.

Question 9.
15+ 46 = _______
Answer:
6 tens and 1 one.

Explanation:
Given that the sum of 15 + 46 is 61. So there are 6 tens and 1 one.

Question 10.
75 + 19 = ________
Answer:
9 tens and 4 ones.

Explanation:
Given that the sum of 75 + 19 is 94. So there are 9 tens and 4 ones.

Question 11.
44 + 47 = _______
Answer:
9 tens and 1 one.

Explanation:
Given that the sum of 44 + 47 is 91. So there are 9 tens and 1 one.

Higher Order Thinking Read the sum. Circle all of the number pairs in the box that match that sum.
Question 12.
Envision Math Common Core 2nd Grade Answer Key Topic 4 Fluently Add Within 100 12
Answer:
12 + 10 = 22
18 + 4 = 22.

Explanation:
The number pairs to get the sum as 22 are 12 + 10 and 18 + 4.
Envision-Math-Common-Core-2nd-Grade-Answer-Key-Topic-4-Fluently-Add-Within-100-12-1

Question 13
Envision Math Common Core 2nd Grade Answer Key Topic 4 Fluently Add Within 100 13
Answer:
25 + 30
45 + 10.

Explanation:
The number pairs to get the sum as 55 are 25 + 30 and 45 + 10.
Envision-Math-Common-Core-2nd-Grade-Answer-Key-Topic-4-Fluently-Add-Within-100-13-1

Question 14.
Envision Math Common Core 2nd Grade Answer Key Topic 4 Fluently Add Within 100 14
Answer:
56 + 27
19 + 64.

Explanation:
The number pairs to get the sum as 83 are 56 + 27 and 19 + 64.
Envision-Math-Common-Core-2nd-Grade-Answer-Key-Topic-4-Fluently-Add-Within-100-14-1

Problem Solving

Solve the problems below. Show your work.
Question 15.
Model Chen counts 47 buttons. Then he counts 20 more buttons. How many buttons does Chen count in all?
________ buttons
Answer:
The total number of buttons does Chen count in all is 67 buttons.

Explanation:
Given that Chen counts 47 buttons and then he counts 20 more buttons. So the total number of buttons does Chen count in all is 47 + 20 which is 67 buttons.

Question 16.
en Vision® STEM There were 24 earthquakes in the U.S. one year. There were 28 earthquakes the next year. How many earthquakes were there in those two years?
________ earthquakes
Answer:
The number of earthquakes in those two years is 52 earthquakes.

Explanation:
Given that there were 24 earthquakes in the U.S in one year and in other year there were 28 earthquakes the next year. So the number of earthquakes is 24 + 28 which is 52 earthquakes.

Question 17.
Higher Order Thinking Write an addition story about the desks and chairs in your classroom. Use pictures, numbers, or words.
Answer:

Question 18.
Assessment Practice Do you have to regroup to find each sum? Choose Yes or No.
Envision Math Common Core 2nd Grade Answer Key Topic 4 Fluently Add Within 100 15
Answer:

Lesson 4.2 Continue to Add 2-Digit Numbers Using Models

Solve & Share
Wendy picked 35 pears. Toni picked 49 pears. How many pears did they pick in all? Use place-value blocks to help explain your work.
I can … add numbers using place value and properties of operations.
Envision Math Common Core 2nd Grade Answer Key Topic 4 Fluently Add Within 100 16

Answer:
The total number of pears that they picked up is 84 pears.

Explanation:
Given that Wendy picked 35 pears andToni picked 49 pears. So the total number of pears that they picked up is 35 + 49 which is 84 pears.
Envision-Math-Common-Core-2nd-Grade-Answer-Key-Topic-4-Fluently-Add-Within-100-16-1

Visual Learning Bridge
Envision Math Common Core 2nd Grade Answer Key Topic 4 Fluently Add Within 100 17

Convince Me! Ken adds 43 + 27. His sum is 60. Is he correct? Explain.

Answer:
No, Ken is not correct.

Explanation:
No, Ken is not correct, because 43 + 27 is 70 but he got the sum as 60.

Guided Practice

Add. Use place value. Draw blocks or use another way.
Question 1.
12 + 23 = ________
Envision Math Common Core 2nd Grade Answer Key Topic 4 Fluently Add Within 100 18

Answer:
The sum of 12 + 23 is 35.

Explanation:
The sum of
12
+23
——
30
5
——
35

Question 2.
18 + 42 = _______
Envision Math Common Core 2nd Grade Answer Key Topic 4 Fluently Add Within 100 19
Answer:
The sum of 18 + 42 is 60.

Question 3.
33 + 48 = ________
Answer:
The sum of 33 +48 is 81

Explanation:
The sum of
33
+48
——
70
11
——
81

Independent Practice

Add. Use place value. Draw blocks or use another way.
Question 4.
18 + 24 = ________
Answer:
The sum of 18 + 24 is 42

Explanation:
The sum of
18
+24
——
30
12
——
42

Question 5.
47 + 38 = ________
Answer:
The sum of 47 + 38 is 85

Explanation:
The sum of
47
+38
——
70
15
——
85

Question 6.
26 + 47 = ________
Answer:
The sum of 26 + 47 is 73

Explanation:
The sum of
26
+47
——
60
13
——
73

Question 7.
34 + 58 = ________
Answer:
The sum of 34 + 58 is 92

Explanation:
The sum of
34
+58
——
80
12
——
92

Question 8.
Higher Order Thinking Draw the second addend.
Envision Math Common Core 2nd Grade Answer Key Topic 4 Fluently Add Within 100 20
Answer:

Problem Solving

Solve each problem. Show your work.
Question 9.
Toby planted 28 trees. Juan planted 36 trees. How many trees did they plant in all?
________ trees
Answer:
The number of trees did they plant in all is 64 trees.

Explanation:
Given that Toby planted 28 trees and Juan planted 36 trees. So the number of trees did they plant in all is 28 + 36 which is 64 trees.

Question 10.
Make Sense Jenny has 13 tennis balls. Sal had 16 tennis balls, but he gave 7 of them to Joe. How many tennis balls do Jenny and Sal have now?
________ tennis balls
Answer:
The number of tennis balls does Jenny and Sal have now is 22 tennis balls.

Explanation:
Given that Jenny has 13 tennis balls and Sal had 16 tennis balls. So the total number of tennis balls is 13 + 16 = 29. He gave 7 of them to Joe, so the number of tennis balls do Jenny and Sal have now is 29 – 7 which is 22 tennis balls.

Question 11.
Higher Order Thinking Write an addition story using two 2-digit numbers. Then solve the problem for your story.
Answer:

Question 12.
Assessment Practice which is the same amount as 28 + 16? Choose all that apply.
Envision Math Common Core 2nd Grade Answer Key Topic 4 Fluently Add Within 100 21
Answer:

Lesson 4.3 Add with Partial Sums

Solve & Share
Ms. Kim’s class has 25 students. Mr. Will’s class has 36 students. Both classes go on a field trip. How many students are on the trip?
Draw place-value blocks to help you solve the problem.
I can … add using place value and partial sums.
___________ students

Visual Learning Bridge
Envision Math Common Core 2nd Grade Answer Key Topic 4 Fluently Add Within 100 22

Convince Me! Can you add the ones first and then the tens | when finding 57 + 28 using partial sums? Explain.

Guided Practice

Add. Use partial sums. Draw blocks if you need to.
Question 1.
24 + 13
Envision Math Common Core 2nd Grade Answer Key Topic 4 Fluently Add Within 100 23
Answer:
The sum of the given numbers is 37.

Explanation:
Given that the numbers to add is 24 and 13. Now we will perform a partial sum of those numbers,
Envision-Math-Common-Core-2nd-Grade-Answer-Key-Topic-4-Fluently-Add-Within-100-23-1

Question 2.
68 + 7
Envision Math Common Core 2nd Grade Answer Key Topic 4 Fluently Add Within 100 24
Answer:
The sum of the given numbers is 75.

Explanation:
Given that the numbers to add is 68 and 7. Now we will perform a partial sum of those numbers,
Envision-Math-Common-Core-2nd-Grade-Answer-Key-Topic-4-Fluently-Add-Within-100-24-1

Independent Practice

Add. Use partial sums. Draw blocks if you need to.
Question 3.
34 + 25
Envision Math Common Core 2nd Grade Answer Key Topic 4 Fluently Add Within 100 25
Answer:
The sum of the given numbers is 59.

Explanation:
Given that the numbers to add is 34 and 25. Now we will perform a partial sum of those numbers,
Envision-Math-Common-Core-2nd-Grade-Answer-Key-Topic-4-Fluently-Add-Within-100-25Envision-Math-Common-Core-2nd-Grade-Answer-Key-Topic-4-Fluently-Add-Within-100-25Envision-Math-Common-Core-2nd-Grade-Answer-Key-Topic-4-Fluently-Add-Within-100-25Envision-Math-Common-Core-2nd-Grade-Answer-Key-Topic-4-Fluently-Add-Within-100-25Envision-Math-Common-Core-2nd-Grade-Answer-Key-Topic-4-Fluently-Add-Within-100-25-1

Question 4.
68 + 18
Envision Math Common Core 2nd Grade Answer Key Topic 4 Fluently Add Within 100 26
Answer:
The sum of the given numbers is 86.

Explanation:
Given that the numbers to add is 68 and 18. Now we will perform a partial sum of those numbers,

Question 5.
37 + 8
Envision Math Common Core 2nd Grade Answer Key Topic 4 Fluently Add Within 100 27
Answer:
The sum of the given numbers is 45.

Explanation:
Given that the numbers to add is 37 and 8. Now we will perform a partial sum of those numbers,
Envision-Math-Common-Core-2nd-Grade-Answer-Key-Topic-4-Fluently-Add-Within-100-27-1

Question 6.
52 + 38
Envision Math Common Core 2nd Grade Answer Key Topic 4 Fluently Add Within 100 28
Answer:
The sum of the given numbers is 90.

Explanation:
Given that the numbers to add is 52 and 38. Now we will perform a partial sum of those numbers,
Envision-Math-Common-Core-2nd-Grade-Answer-Key-Topic-4-Fluently-Add-Within-100-28-1Envision-Math-Common-Core-2nd-Grade-Answer-Key-Topic-4-Fluently-Add-Within-100-28-1Envision-Math-Common-Core-2nd-Grade-Answer-Key-Topic-4-Fluently-Add-Within-100-28-1Envision-Math-Common-Core-2nd-Grade-Answer-Key-Topic-4-Fluently-Add-Within-100-28-1Envision-Math-Common-Core-2nd-Grade-Answer-Key-Topic-4-Fluently-Add-Within-100-28-1

Question 7.
45 + 29
Envision Math Common Core 2nd Grade Answer Key Topic 4 Fluently Add Within 100 29
Answer:
The sum of the given numbers is 74.

Explanation:
Given that the numbers to add is 45 and 29. Now we will perform a partial sum of those numbers,
Envision-Math-Common-Core-2nd-Grade-Answer-Key-Topic-4-Fluently-Add-Within-100-29-1

Question 8.
28 + 39
Envision Math Common Core 2nd Grade Answer Key Topic 4 Fluently Add Within 100 30
Answer:
The sum of the given numbers is 67.

Explanation:
Given that the numbers to add is 28 and 39. Now we will perform a partial sum of those numbers,
Envision-Math-Common-Core-2nd-Grade-Answer-Key-Topic-4-Fluently-Add-Within-100-30-1

Number Sense Write each missing tens or ones digit.
Question 9.
23 + 1☐ = 37
Answer:
23 + 14 = 37.

Explanation:
To find the missing digit, we will do subtraction
37 – 23  = 14.
Here, the missing digit is 4.

Question 10.
59 = ☐8 + 31
Answer:
59 = 28 + 31.

Explanation:
To find the missing digit, we will do subtraction
59 – 31 = 28
Here, the missing digit is 2.

Problem Solving

Solve each problem. Show your work.
Question 11.
Model 34 students are on the playground. 17 students are in the gym. How many students are there in all?
_________ students
Answer:
The number of students are there in all is 51 students.

Explanation:
Given that 34 students are on the playground and 17 students are in the gym. So the number of students are there in all is 34 + 17 which is 51 students.

Question 12.
Sarah put 8 white roses in a vase. Then she added 7 red roses and 12 yellow roses to the vase. How many roses are in the vase now?
_______ roses
Answer:
The number of roses is in the vase now is 27 roses.

Explanation:
Given that Sarah put 8 white roses in a vase and then she added 7 red roses and 12 yellow roses to the vase. So the number of roses are in the vase now is 8 + 7 + 12 which is 27 roses.

Envision Math Common Core 2nd Grade Answers Topic 4 Fluently Add Within 100 31

Question 13.
Higher Order Thinking Write each missing tens or ones digit. What strategy did you use?
12 + 3☐ = 50
24 + 3☐ = 60
35 + 3☐ = 70
Answer:
The missing digits are 8, 6, 5.

Explanation:
To find the missing digit, we will do subtraction
50 – 12 = 38.
Here, the missing digit is 8.
To find the missing digit, we will do subtraction
60 – 24 = 36.
Here, the missing digit is 6.
To find the missing digit, we will do subtraction
70 – 35 = 35
Here, the missing digit is 5.

Question 14.
Assessment Practice which is the sum of 28 + 36? Use partial sums to solve.
A. 8
B. 12
C. 54
D. 64
Answer:
The sum of 28 + 36 is 64.

Explanation:
The partial sum of 28 + 36 is
28
+ 36
——————–
20 + 30 = 50
8 + 6     = 14
——————–
64

Lesson 4.4 Add Using Mental Math and Partial Sums

Solve & Share
Add 46 + 26. Explain how you solved the problem.

I can … add numbers using place value and partial sums.

Visual Learning Bridge
Envision Math Common Core 2nd Grade Answers Topic 4 Fluently Add Within 100 32

Convince Me! Roger found 54 + 27. His sum was 71. Is he correct? Why or why not? Use partial sums to check.

Answer:
Roger is not correct.

Explanation:
Given that Roger found 54 + 27. His sum was 71, let’s check using the partial sum
54
+ 27
——————–
50 + 20 = 70
4 + 7     = 11
——————–
81
Roger is not correct, because the sum of 54 + 27 is 81.

Guided Practice

Write the addition problem. Use partial sums. Add any way you choose. Show your work.
Question 1.
34 + 17
Envision Math Common Core 2nd Grade Answers Topic 4 Fluently Add Within 100 33
Answer:
The sum of 34 + 17 is 51.

Explanation:
The partial sum of 34 + 17 is 51.
Envision-Math-Common-Core-2nd-Grade-Answers-Topic-4-Fluently-Add-Within-100-33-1

Question 2.
52 + 31
Envision Math Common Core 2nd Grade Answers Topic 4 Fluently Add Within 100 33
Answer:
The sum of 52 + 31 is 83.

Explanation:
The partial sum of 52 + 31 is 83.
Envision-Math-Common-Core-2nd-Grade-Answers-Topic-4-Fluently-Add-Within-100-33-2

Question 3.
35 + 26
Envision Math Common Core 2nd Grade Answers Topic 4 Fluently Add Within 100 33
Answer:
The sum of 35 + 26 is 61.

Explanation:
The partial sum of 35 + 26 is 61.
Envision-Math-Common-Core-2nd-Grade-Answers-Topic-4-Fluently-Add-Within-100-33-3

Independent Practice

Write the addition problem. Use partial sums. Add any way you choose. Show your work.
Question 4.
15 + 28
Envision Math Common Core 2nd Grade Answers Topic 4 Fluently Add Within 100 33
Answer:
The sum of 15 + 28 is 43.

Explanation:
The partial sum of 15 + 28 is 43.
Envision-Math-Common-4Core-2nd-Grade-Answers-Topic-4-Fluently-Add-Within-100-33-4

Question 5.
29 + 20
Envision Math Common Core 2nd Grade Answers Topic 4 Fluently Add Within 100 33
Answer:
The sum of 29 + 20 is 49.

Explanation:
The partial sum of 29 + 20 is 49.
Envision-Math-Common-Core-2nd-Grade-Answers-Topic-4-Fluently-Add-Within-100-33-5

Question 6.
63 + 29
Envision Math Common Core 2nd Grade Answers Topic 4 Fluently Add Within 100 33
Answer:
The sum of 63 + 29 is 92.

Explanation:
The partial sum of 63 + 29 is 92.
Envision-Math-Common-Core-2nd-Grade-Answers-Topic-4-Fluently-Add-Within-100-33-6

Question 7.
37 + 48
Envision Math Common Core 2nd Grade Answers Topic 4 Fluently Add Within 100 33
Answer:
The sum of 37 + 48 is 85.

Explanation:
The partial sum of 37 + 48 is 85.
Envision-Math-Common-Core-2nd-Grade-Answers-Topic-4-Fluently-Add-Within-100-33-7

Add any way you choose. Show your work.
Question 8.
67 + 17 = ________
Answer:
The sum of 67 + 17 is 84.

Explanation:
The partial sum of 67 + 17 is 84.
Envision-Math-Common-Core-2nd-Grade-Answers-Topic-4-Fluently-Add-Within-100-33-8

Question 9.
15 + 18 = ________
Answer:
The sum of 15 + 18 is 33.

Explanation:
The partial sum of 15 + 18 is 33.
Envision-Math-Common-Core-2nd-Grade-Answers-Topic-4-Fluently-Add-Within-100-33-9

Question 10.
43 + 49 = ________
Answer:
The sum of 43 + 49 is 92.

Explanation:
The partial sum of 43 + 49 is 92.
Envision-Math-Common-Core-2nd-Grade-Answers-Topic-4-Fluently-Add-Within-100-33-10

Question 11.
62 + 28 = ________
Answer:
The sum of 62 + 28 is 90.

Explanation:
The partial sum of 62 + 28 is 90.
Envision-Math-Common-Core-2nd-Grade-Answers-Topic-4-Fluently-Add-Within-100-33-11

Number Sense Write the missing ones or tens digits.
Question 12.
27 + 2☐ = 50
Answer:
The missing digit is 3.

Explanation:
To find the missing digit, we will do subtraction
50 – 27 = 23.
Here, the missing digit is 3.

Question 13.
3☐ + 16 = 48
Answer:
The missing digit is 2.

Explanation:
To find the missing digit, we will do subtraction
48 – 16 = 32.
Here, the missing digit is 2.

Question 14.
☐4 + 49 = 93
Answer:
The missing digit is 4.

Explanation:
To find the missing digit, we will do subtraction
93 – 49 = 44.
Here, the missing digit is 4.

Problem Solving

Solve each problem. Show your work. Use drawings, if needed.
Question 15.
Amir plants 25 trees. Juan plants 27 trees. How many trees do they plant in all?
________ trees
Answer:
The total number of trees do they plant in all is 52 trees.

Explanation:
Given that Amir plants 25 trees and Juan plant 27 trees, so the total number of trees do they plant in all is 25 + 27 which is 52 trees.

Question 16.
On Monday, Sasha puts 32 pennies in her bank. On Tuesday, she puts 57 more pennies in her bank. How many pennies does she put in her bank on both days?
________ pennies
Answer:
The number of pennies does she puts in her bank on both days is 89 pennies.

Explanation:
Given that, on Monday, Sasha puts 32 pennies in her bank, and on Tuesday, she puts 57 more pennies in her bank. So the number of pennies does she puts in her bank on both days is 32 + 57 which is 89 pennies.

Question 17.
Higher Order Thinking Write an addition story using 2 two-digit numbers. Then solve the problem for your story.
Answer:
The number of toffies is there in all is 86 toffies.

Explanation:
There are 60 toffies in a jar. Harry adds 26 toffies more. How many toffies are there in all?

Answer:
Given that there are 60 toffies in a jar and Harry adds 26 toffies more. So the number of toffies are there in all is 60 +26 which is 86 toffies.

Question 18.
Assessment Practice Find 52 + 39 using partial sums. Show how you solved the problem.
52 + 39 = ________
Answer:
The sum of 52 + 39 is 91.

Explanation:
The partial sum of 52 + 39 is 91
52
+ 39
——————–
50 + 30 = 80
2 + 9     = 11
——————–
91

Lesson 4.5 Break Apart Numbers and Add Using Mental Math

Solve & Share
Monica has 24 crayons. Paul has 64 crayons. How many crayons do they have in all? Use place-value blocks or draw a picture to explain your work.

I can … add within 100 using place value strategies.
Envision Math Common Core 2nd Grade Answers Topic 4 Fluently Add Within 100 34

Answer:
The number of crayons do they have is 88 crayons.

Explanation:
Given that Monica has 24 crayons and Paul has 64 crayons. So the number of crayons do they have is 64 + 24 which is 88 crayons.

Visual Learning Bridge
Envision Math Common Core 2nd Grade Answers Topic 4 Fluently Add Within 100 35

Convince Me! Explain one way you can break apart numbers to find 14 + 32.

Guided Practice

Find each sum using mental math. Draw pictures of blocks if needed.
Question 1.
Envision Math Common Core 2nd Grade Answers Topic 4 Fluently Add Within 100 36
Answer:
The sum of 17 + 52 is 69.

Explanation:
The sum of 17 + 52 is
17 + (50 + 2)
= (17 + 50) +2
= 67 + 2
= 69.

Question 2.
Envision Math Common Core 2nd Grade Answers Topic 4 Fluently Add Within 100 37
Answer:
The sum of 69 + 23 is 92.

Explanation:
The sum of 69 + 23 is
69 + (20 + 3)
= (69 + 20) +3
= 89 + 3
= 92.
Envision-Math-Common-Core-2nd-Grade-Answers-Topic-4-Fluently-Add-Within-100-37-1

Independent Practice

Find each sum using mental math. Draw pictures of blocks if needed.
Question 3.
Envision Math Common Core 2nd Grade Answers Topic 4 Fluently Add Within 100 38
Answer:
The sum of 23 + 26 is 49.

Explanation:
The sum of 23 + 26 is
23 + (20 + 6)
= (23 + 20) +6
= 43 + 6
= 49.
Envision-Math-Common-Core-2nd-Grade-Answers-Topic-4-Fluently-Add-Within-100-38-1

Question 4.
Envision Math Common Core 2nd Grade Answers Topic 4 Fluently Add Within 100 39
Answer:
The sum of 9 + 42 is 51.

Explanation:
The sum of 9 + 42 is
9 + (40 + 2)
= (9 + 40) + 2
= 49 + 2
= 51.
Envision-Math-Common-Core-2nd-Grade-Answers-Topic-4-Fluently-Add-Within-100-39-1

Question 5.
Envision Math Common Core 2nd Grade Answers Topic 4 Fluently Add Within 100 40
Answer:
The sum of 51 + 16 is 67.

Explanation:
The sum of 51 + 16 is
51 + (10 + 6)
= (51 + 10) + 6
= 61 + 6
= 67.
Envision-Math-Common-Core-2nd-Grade-Answers-Topic-4-Fluently-Add-Within-100-40-1

Question 6.
56 + 15 = _______
Answer:
The sum of 56 + 15 is 71.

Explanation:
The sum of 56 + 15 is
56 + (10 + 5)
= (56 + 10) + 5
= 66 + 5
= 71.

Question 7.
_______ = 76 + 18
Answer:
The sum of 76 + 18 is 94.

Explanation:
The sum of 76 + 18 is
76 + (10 + 8)
= (76 + 10) + 8
= 86 + 8
= 94.

Question 8.
33 + 49 = ________
Answer:
The sum of 33 + 49 is 82.

Explanation:
The sum of 33 + 49 is
33 + (40 + 9)
= (33 + 40) + 9
= 73 + 9
= 82.

Add tens and ones to solve.
Question 9.
Algebra One number makes both equations true. Find the missing number.
17 + ☐ = 28
☐ + 28 = 39
Answer:
The missing digit is 11.

Explanation:
To find the missing digit, we will do subtraction
28 – 17 = 11.
Here, the missing digit is 11.
To find the missing digit, we will do subtraction
39 – 28 = 11.
Here, the missing digit is 11.

Problem Solving

Generalize Solve each problem mentally. Show your work. Think about the steps you do every time you break apart numbers to add.
Question 10.
Billy puts 34 skateboard wheels in a pile. He puts 34 more wheels in another pile. How many wheels does Billy have in all?
_________ wheels
Answer:
The number of wheels does Billy has in all is 68 wheels.

Explanation:
Given that Billy puts 34 skateboard wheels in a pile and he puts 34 more wheels in another pile. So the number of wheels does Billy has in all is 34 + 34 which is 68 wheels.

Question 11.
enVision® STEM A new office and house were built in a town. 24 windows are needed for the office. 18 windows are needed for the house. How many windows are needed in all?
_________ windows
Answer:
The number of windows is 42 windows.

Explanation:
Given that a new office and house were built in a town with 24 windows are needed for the office and 18 windows are needed for the house. So the number of windows 24 + 18 which 42 windows.

Question 12.
Higher Order Thinking Write a story problem about 14 + 41. Then solve the problem.
14 + 41 = ________
Answer:

Question 13.
Assessment Practice Use mental math to find 15 + 12. Explain why the strategy works.
Answer:
The sum of 15 + 12 is 27.

Explanation:
The sum of 15 + 12 is
15 + (10 + 2)
= (15 + 10) + 2
= 25 + 2
= 27.

Lesson 4.6 Add More than Two 2-Digit Numbers

Solve & Share
12 + 34 + 28 = ?
Tom says he can find the sum by adding 28 and 12 first. He says he can add 34 to that sum to find the total.
Do you agree? Use pictures, words, and numbers to make a math argument. Then solve the problem. Show your work.

I can … add three or four 2-digit numbers.
Envision Math Common Core 2nd Grade Answers Topic 4 Fluently Add Within 100 41

Visual Learning Bridge
Envision Math Common Core 2nd Grade Answers Topic 4 Fluently Add Within 100 42

Convince Me! Look above. Why do you think the order of the addends changed? Why do you think 24 and 16 were added together?

Guided Practice

Add. Use any strategy. Show your work.
Question 1.
18+ 15 + 12 = _______
Envision Math Common Core 2nd Grade Answers Topic 4 Fluently Add Within 100 43

Question 2.
11 + 14 + 39 = ________
Answer:
11 + 14 + 39 = 64.

Explanation:
Given that 11 + 14 + 39
= 25 + 39
= 64.

Question 3.
21 + 14 + 41 + 22 = ________
Answer:
21 + 14 + 41 + 22 = 98.

Explanation:
Given that 21 + 14 + 41 + 22
= 35 + 63
= 98.

Question 4.
21 + 15 + 32 + 25 = ________
Answer:
21 + 15 + 32 + 25 = 93.

Explanation:
Given that 21 + 15 + 32 + 25
= 36 + 57
= 93.

Independent Practice

Add. Use any strategy. Show your work.
Question 5.
27 + 21 + 13 = ________
Answer:
27 + 21 + 13 = 61.

Explanation:
Given that 27 + 21 + 13
= 48 +13
= 61.

Question 6.
16 + 32 + 28 = ________
Answer:
16 + 32 + 28 = 76.

Explanation:
Given that 16 + 32 + 28
= 48 + 28
= 76.

Question 7.
32 + 14 + 42 = ________
Answer:
32 + 14 + 42 = 88.

Explanation:
Given that 32 + 14 + 42
= 46 + 42
= 88.

Question 8.
25 + 17 + 24 + 15 = ________
Answer:
25 + 17 + 24 + 15 = 81.

Explanation:
Given that 25 + 17 + 24 + 15
= 42 + 39
= 81.

Question 9.
32 + 16 + 18 + 31 = ________
Answer:
32 + 16 + 18 + 31 = 97.

Explanation:
Given that 32 + 16 + 18 + 31
= 48 + 49
= 97.

Question 10.
37 + 11 + 13 + 38 = ________
Answer:
37 + 11 + 13 + 38 = 99.

Explanation:
Given that 37 + 11 + 13 + 38
= 48 + 51
= 99.

Algebra Find the missing numbers.
Question 11.
8 + 3 + Envision Math Common Core 2nd Grade Answers Topic 4 Fluently Add Within 100 44 + 2 = 18
Answer:
The missing digit is 5.

Explanation:
Let the missing number be X, 8 + 3 + X + 2 = 18 which is 13 + X = 18.
To find the missing digit, we will do subtraction
X = 18 – 13
= 5.
Here, the missing digit is 5.

Question 12.
5 + Envision Math Common Core 2nd Grade Answers Topic 4 Fluently Add Within 100 44 + 6 + 5 = 19
Answer:
The missing digit is 3.

Explanation:
Let the missing number be X, 5 + X + 6 + 5 = 19 which is 16 + X = 19.
To find the missing digit, we will do subtraction
X = 19 – 16
= 3.
Here, the missing digit is 3.

Question 13.
7 + 27 + 23 + Envision Math Common Core 2nd Grade Answers Topic 4 Fluently Add Within 100 44 = 61
Answer:
The missing digit is 4.

Explanation:
Let the missing number be X, 7 + 27 + 23 + X = 61 which is 57 + X = 61.
To find the missing digit, we will do subtraction
X = 61 – 57
= 4.
Here, the missing digit is 4.

Question 14.
Envision Math Common Core 2nd Grade Answers Topic 4 Fluently Add Within 100 44 + 24 + 18+ 4 = 52
Answer:
The missing digit is 6.

Explanation:
Let the missing number be X, X + 24 + 18 + 4 = 52 which is 46 + X = 52.
To find the missing digit, we will do subtraction
X = 52 – 46
= 6.
Here, the missing digit is 6.

Problem Solving

Reasoning Solve each problem. Show your work.
Question 15.
28 trucks are blue. 32 trucks are yellow. 17 trucks are green. Il trucks are pink. How many trucks are there in all?
Envision Math Common Core 2nd Grade Answers Topic 4 Fluently Add Within 100 45
_______ trucks
Answer:
The total number of trucks is 88 trucks.

Explanation:
Given that there are 28 blue trucks, 32 yellow trucks and 17 green trucks, and 11 pink trucks. So the total number of trucks are 28 + 32 + 17 + 11 which is 88 trucks.

Question 16.
Joel won 19 tickets in March, 24 tickets in April, 23 tickets in May, and 16 tickets in June. How many tickets does Joel have in all?
_________ tickets
Answer:
The number of tickets Joel has in all is 82 tickets.

Explanation:
Given that Joel won 19 tickets in March, 24 tickets in April, 23 tickets in May, and 16 tickets in June. So the number of tickets Joel have in all is 19 + 24 + 23 + 16 =  82 tickets.

Question 17.
Higher Order Thinking Henry is adding the numbers 24, 18, and 36. He makes a ten to add. Which ones digits does Henry add first? Explain.
Envision Math Common Core Grade 2 Answer Key Topic 4 Fluently Add Within 100 46
Answer:

Question 18.
Assessment Practice Find the sum. Use any strategy. Show your work.
25 + 16 + 15 + 38 = _________
Answer:
The sum of 25 + 16 + 15 + 38 = 94.

Explanation:
Given that 25 + 16 + 15 + 38
= 41 + 53
= 94.

Lesson 4.7 Practice Adding Using Strategies

Solve & Share
Maria has 39 stickers. Sally has 28 stickers. They found 14 more stickers. How many stickers do they have in all? Solve. Use any strategy. Explain how you found the answer.
I can … use mental math, strategies, and models to add two, three, or four numbers.
Envision Math Common Core Grade 2 Answer Key Topic 4 Fluently Add Within 100 47

Visual Learning Bridge
Envision Math Common Core Grade 2 Answer Key Topic 4 Fluently Add Within 100 48

Convince Me! Find the sum of 14 + 28 +33 + 22. Explain.

Guided Practice

Add. Use any strategy. Show your work.
Question 1.
18 + 43 + 12 = _______
Envision Math Common Core Grade 2 Answer Key Topic 4 Fluently Add Within 100 49
Answer:

Question 2.
29 + 47 = _______
Answer:
The sum of 29 + 47 = 76.

Explanation:
Given that 29 + 47 which is
20 + 40 = 60
9 + 7 = 16
60 + 16 = 76.

Question 3.
9 + 34 + 21 = _______
Answer:
The sum of 9 + 34 + 21 is 64.

Explanation:
Given that 9 + 34 + 21 which is
30 + 20 = 50
9 + 4 + 1 = 14
50 + 14 = 64.

Question 4.
33 + 27 + 18 + 13 = _______
Answer:
The sum of 33 + 27 + 18 + 13 = 91.

Explanation:
Given that 33 + 27 + 18 + 13 which is
30 + 20 + 10 + 10 = 70
3 + 7 + 8 + 3 = 21
70 + 21 = 91.

Independent Practice

Add. Use any strategy. Show your work.
Question 5.
31 + 5 + 29 = _______
Answer:
The sum of 31 + 5 + 29 = 65.

Explanation:
Given that 31 + 5 + 29 which is
30 + 20 = 50
1 + 5 + 9 =15
50 + 15 = 65.

Question 6.
20 + 18 + 16 = _______
Answer:
The sum of 20 + 18 + 16 = 54.

Explanation:
Given that 20 + 18 + 16 which is
20 + 10 + 10 = 40
8 + 6 = 14
40 + 14 = 54.

Question 7.
8 + 17 = _______
Answer:
The sum of 8 + 17 is 25.

Explanation:
Given that 8 + 17
8 + 7 = 15
10 + 15 = 25.

Add. Use partial sums. Think about compatible numbers.
Question 8.
Envision Math Common Core Grade 2 Answer Key Topic 4 Fluently Add Within 100 50
Answer:
The sum of 25 + 13 + 12 + 5 = 55.

Explanation:
Given that 25 + 13 + 12 + 5 which is
20 + 10 + 10 = 40
5 + 3 + 2 + 5 = 15
40 + 15 = 55.

Question 9.
Envision Math Common Core Grade 2 Answer Key Topic 4 Fluently Add Within 100 51
Answer:
The sum of 9 + 29 + 5 + 35 = 70.

Explanation:
The sum of 9 + 29 + 5 + 35 which is
20 + 30 = 50
9 + 9 + 5 + 5 = 28
50 + 28 = 78.

Question 10.
Envision Math Common Core Grade 2 Answer Key Topic 4 Fluently Add Within 100 52
Answer:
The sum of 18 + 24 + 42 + 6 is 90.

Explanation:
The sum of 18 + 24 + 42 + 6 which is
10 + 20 + 40 = 70
8 + 4 + 2 + 6 = 20
70 + 20 = 90.

Question 11.
Envision Math Common Core Grade 2 Answer Key Topic 4 Fluently Add Within 100 53
Answer:
The sum of 27 + 15 + 33 + 24 = 99.

Explanation:
The sum of 27 + 15 + 33 + 24 is
20 + 10 + 30 + 20 = 80
7 + 5 + 3 + 4 = 19
80 + 19 = 99.

Question 12.
Envision Math Common Core Grade 2 Answer Key Topic 4 Fluently Add Within 100 54
Answer:
The sum of 13 + 7 + 20 + 55 = 95.

Explanation:
The sum of 13 + 7 + 20 + 55 is
10 + 20 + 50 = 80
3 + 7 + 5 = 15
80 + 15 = 95.

Number Sense Solve each problem. In which order did you add the numbers? Explain.
Question 13.
22 + 17 + 8 + 3 = ________
Answer:
The sum of 22 + 17 + 8 + 3 is 50.

Explanation:
The sum of 22 + 17 + 8 + 3 is
20 + 10 = 30
2 + 7 + 8 + 3 = 20
30 + 20 = 50.

Question 14.
5 + 12 + 15 + 3 = ________
Answer:
The sum of 5 + 12 + 15 + 3 = 35.

Explanation:
The sum of 5 + 12 + 15 + 3 is
10 + 10 = 20
5 + 2 + 5 + 3 = 15
20 + 15 = 35.

Problem Solving

Solve each problem. Show your work.
Question 15.
Model Kim has 38 seashells. Mike has 27 seashells. Use partial sums to find how many shells they have in all. Then check your answer by adding another way.
__________ seashells
Answer:
The number of shells they have in all is 65 seashells.

Explanation:
Given that Kim has 38 seashells and Mike has 27 seashells. So the number of shells they have in all is 38 + 27 which is
30 + 20 = 50
8 + 7 = 15.
50 + 15 = 65.

Question 16.
en Vision® STEM Fossils form slowly over millions of years. Many fossils come from the sea. Kyle has 9 fossils, Jorie has 12 fossils, Leah has 6 fossils, and Joshua has 8 fossils. How many fossils do they have in all?
Envision Math Common Core Grade 2 Answer Key Topic 4 Fluently Add Within 100 55
__________ fossils
Answer:
The total number of fossils do they have in all is 35 fossils.

Explanation:
Given that Kyle has 9 fossils, Jorie has 12 fossils, Leah has 6 fossils, and Joshua has 8 fossils. So the total number of fossils do they have in all is 9 + 12 + 6 + 8 which is
9 + 6 + 8 + 2 = 25
10 + 25 = 35.

Question 17.
Higher Order Thinking Find the sum of 42 + 13 + 18 + 7 = _________ . Explain why your strategy works.
Answer:
The sum of 42 + 13 + 18 + 7 is 80.

Explanation:
The sum of 42 + 13 + 18 + 7 is
40 + 10 + 10 = 60
2 + 3 + 8 + 7 = 20
60 + 20 = 80.

Question 18.
Assessment Practice Find the sum of 17 + 29 + 46. Use any strategy. Show your work.
17 + 29 + 46 = __________
Answer:
The sum of 17 + 29 + 46 = 92.

Explanation:
The sum of 17 + 29 + 46 is
10 + 20 + 40 = 70
7 + 9 + 6 = 22
22 + 70 = 92.

Lesson 4.8 Solve One-Step and Two-Step Problems

Solve & Share
The second graders take a trip to a nature center. The Green Class sees 23 animals. The Blue Class sees 14 animals. The Yellow Class sees 32 animals. How many animals do they see in all?
Solve using drawings, models, or an equation. Be prepared to explain your work.

I can … use drawings, models, and equations to solve one- and two-step problems.
Envision Math Common Core Grade 2 Answer Key Topic 4 Fluently Add Within 100 56
_________ animals

Answer:
The total number of animals do they see all is 69 animals.

Explanation:
Given that the second graders take a trip to a nature center. The Green Class sees 23 animals and the Blue Class sees 14 animals and the Yellow Class sees 32 animals. So the total number of animals do they see all is 23 + 14 + 32 which is
= 37 + 32
= 69 animals.

Visual Learning Bridge
Envision Math Common Core Grade 2 Answer Key Topic 4 Fluently Add Within 100 57

Convince Me! What is a different way you can use mental math to find 36 + ? = 53?

Answer:
36 + 17 = 53.

Explanation:
The different way we can use mental math is to find 36 + ? = 53 is first we will add 10 to the number 36 then we will get 36 + 10 which is 46 and here the result is 53, so we need to add 7 more. So it will be 46 + 7 which is 53.

Guided Practice

Use the bar diagram and mental math to solve each problem. Then check your work.
Question 1.
Bruce buys 18 eggs. He uses 10 of them for baking. Then he buys 36 more eggs. How many eggs does Bruce have now?
Check:
Envision Math Common Core Grade 2 Answer Key Topic 4 Fluently Add Within 100 58
________ eggs
Answer:
The total number of eggs is 44 eggs.

Explanation:
Given that Bruce buys 18 eggs and he uses 10 of them for baking, so the number of eggs will be 18 – 10 which is 8 eggs. And then he buys 36 more eggs. So the number of eggs will be 8 + 36 which is 44 eggs.

Independent Practice

Use the bar diagram(s) and mental math to solve each problem. Then check your work.
Question 2.
Ella has 34 more buttons than Julio. Julio has 49 buttons. How many buttons does Ella have?
Check
Envision Math Common Core Grade 2 Answer Key Topic 4 Fluently Add Within 100 59
________ buttons
Answer:
The number of buttons does Ella has now is 83 buttons.

Explanation:
Given that Ella has 34 more buttons than Julio and Julio has 49 buttons. So the number of buttons does Ella has now is 49 + 34 which is 83 buttons.
Envision-Math-Common-Core-Grade-2-Answer-Key-Topic-4-Fluently-Add-Within-100-59-1

Question 3.
20 students are on the bus. Then 10 students get off the bus. Next, 15 students get on the bus. How many students are on the bus now?
Check:
Envision Math Common Core Grade 2 Answer Key Topic 4 Fluently Add Within 100 60
________ students
Answer:
The total number of students will be 25 students.

Explanation:
Given that there are 20 students are on the bus and then 10 students get off the bus. So the number of students will be 20 – 10 which is 10 students. And then 15 students get on the bus, so the number of students now is 10 + 15  which is 25 students. So the total number of students will be 25 students.
Envision-Math-Common-Core-Grade-2-Answer-Key-Topic-4-Fluently-Add-Within-100-60-1

Question 4.
Wendy has 14 more crayons than Oscar. Oscar has 54 crayons. How many crayons does Wendy have?
Envision Math Common Core Grade 2 Answer Key Topic 4 Fluently Add Within 100 61
_________ crayons
Answer:
The number of crayons Wendy has is 68 crayons.

Explanation:
Given that Wendy has 14 more crayons than Oscar and Oscar has 54 crayons. So the number of crayons Wendy has is 54 + 14 which is 68 crayons.
Envision-Math-Common-Core-Grade-2-Answer-Key-Topic-4-Fluently-Add-Within-100-61-1

Problem Solving

Solve each problem. Show your work.
Question 5.
Make Sense Mariah has 17 figs. Kendra has 20 more figs than Mariah. Toby has 33 more figs than Kendra. How many figs do Kendra and Toby each have?
Step 1:
How many figs does Kendra have?
________ Envision Math Common Core Grade 2 Answer Key Topic 4 Fluently Add Within 100 62 _______ = ________ figs
Step 2: How many figs does Toby have?
________ Envision Math Common Core Grade 2 Answer Key Topic 4 Fluently Add Within 100 62 _______ = ________ figs
Solve one step at a time.
Answer:
Kendra has 17 + 20 = 37 figs.
Toby has 37 + 33 = 70 figs.

Explanation:
Given that Mariah has 17 figs and Kendra has 20 more figs than Mariah, so the number of figs does Kendra has now is 17 + 20 which is 37 figs.
Toby has 33 more figs than Kendra, so the number of figs does Toby has now is 37 + 33 which is 70 figs.

Question 6.
Higher Order Thinking 8 girls and some boys are in the pool. In all, 17 children are in the pool. Then some more boys jump in the pool. Now there are 13 boys in the pool. How many more boys jumped in the pool?
Step 1:
________ Envision Math Common Core Grade 2 Answer Key Topic 4 Fluently Add Within 100 62 _______ = ________
Step 2:
________ Envision Math Common Core Grade 2 Answer Key Topic 4 Fluently Add Within 100 62 _______ = ________
_________ more boys jumped in the pool
Answer:
4 more boys jumped in the pool.

Explanation:
Given that 8 girls and some boys are in the pool. In all, 17 children are in the pool, so the number of boys in the pool is 17 – 8 which is 9 boys. As some boys jump into the pool and the boys in the pool are 13. So the number of boys who jumped in the pool is 13 – 9 which is 4 boys.

Question 7.
Assessment Practice The soccer coach has 18 shirts. She gives 9 of the shirts to some of her players. Then she gets 11 more shirts. How many shirts does the coach have left?
Show how you can solve the problem in two steps.
Step 1:
Step 2:
The coach has ________ shirts left.
Answer:
The coach has 20 shirts left.

Explanation:
Given that the soccer coach has 18 shirts and she gives 9 of the shirts to some of her players, so the number of shirts does coach had is 18 – 9 which is 9 shirts. And then gets 11 more shirts, so the total number of shirts does the coach has left is 9 + 11 which is 20 shirts.

Lesson 4.9 Problem Solving

Model with Math
Solve & Share
Kim puts 25 toys into an empty toy box. Then she puts 17 more toys in the toy box. How many toys are in the box in all?
Use a model to show the problem. Be ready to explain how your model helps you solve the problem.

I can … make models to help solve math problems.
Envision Math Common Core Grade 2 Answer Key Topic 4 Fluently Add Within 100 63

Answer:
The total number of toys in the box is 42 toys.

Explanation:
Given that Kim puts 25 toys into an empty toy box and then she puts 17 more toys in the toy box. So the total number of toys in the box is 25 + 17 which is 42 toys.
Envision-Math-Common-Core-Grade-2-Answer-Key-Topic-4-Fluently-Add-Within-100-63-1

Thinking Habits
Can I write an equation or use a drawing, diagram, table, graph, or objects to show the problem?

Visual Learning Bridge
Envision Math Common Core Grade 2 Answer Key Topic 4 Fluently Add Within 100 64

Convince Me! How does drawing a bar diagram or writing an equation model a problem? Is there another way to model the problem?

Answer:
Here, both the bar diagram and writing an equation model for a problem works.

Guided Practice

Complete the bar diagram. Write an equation to model the problem. Then solve.
Question 1.
Flora has 24 books about birds. She has 18 books about bugs. How many books is that?
Envision Math Common Core Grade 2 Answer Key Topic 4 Fluently Add Within 100 65

Answer:
The number of books is 42 books.

Explanation:
Given that Flora has 24 books about birds and she has 18 books about bugs. So the number of books is 24 + 18 which is 42 books.

Question 2.
Barb saw 14 cars on Smith Street. She saw 8 cars on Alfred Street. How many more cars did Barb see on Smith Street?
Envision Math Common Core Grade 2 Answer Key Topic 4 Fluently Add Within 100 66
_______ Envision Math Common Core Grade 2 Answer Key Topic 4 Fluently Add Within 100 62 _______ = ________ cars
Answer:
The number of cars did Barb see on Smith Street is 22 cars.

Explanation:
Given that Barb saw 14 cars on Smith Street and she saw 8 cars on Alfred Street. So the number of cars did Barb see on Smith Street is 14 + 8 which is 22 cars.
Envision-Math-Common-Core-Grade-2-Answer-Key-Topic-4-Fluently-Add-Within-100-66-1

Independent Practice

Make a model to show each problem. Then use the model to solve. Show your work.
Question 3.
Avi takes 16 pictures. Then he takes 17 more pictures. How many pictures does Avi take?
Envision Math Common Core Grade 2 Answer Key Topic 4 Fluently Add Within 100 67
Answer:
The number of pictures does Avi take is 33 pictures.

Explanation:
Given that Avi takes 16 pictures and then he takes 17 more pictures. So the number of pictures does Avi take is 16 + 17 which is 33 pictures.

Question 4.
Tina picks 55 blueberries. Next, Tina eats 6 of these blueberries. Then she picks 27 more. How many blueberries does she have now?
Answer:
The number of blueberries does she have now is 76 blueberries.

Explanation:
Given that Tina picks 55 blueberries and Tina eats 6 of these blueberries, so the number of blueberries is 55 – 6 which is 49 blueberries. Now she picks 27 more, so the number of blueberries does she have now is 49 + 27 which is 76 blueberries.

Question 5.
Raj finds 47 acorns in his front yard. He finds 29 acorns in his back yard. How many acorns does Raj find in all?
Answer:
The number of acorns does Raj finds in all is 76 acorns.

Explanation:
Given that Raj finds 47 acorns in his front yard and he finds 29 acorns in his back yard. So the number of acorns does Raj finds in all is 47 + 29 which is 76 acorns.

Problem Solving

Performance Task
African Safari The Santos family is on an African safari. The chart at the right shows the number of animals they see. How many animals do they see?
Envision Math Common Core Grade 2 Answer Key Topic 4 Fluently Add Within 100 68

Question 6.
Make Sense What do you know? What are you asked to find?
Answer:
Here, we know that how many animals they saw of each type of animal and we need to find the total.

Question 7.
Model Make a model to help you find the number of animals they see. Be ready to explain why you chose the model you did.
Answer:
The number of animals they see is 51 animals.

Explanation:
Given that there are 15 giraffes, 9 elephants, 16 lions and 11 zebras. So the number of animals they see are 15 + 9 + 16 + 11
= 24 + 27
= 51.

Question 8.
Model What other model could you use to show the problem? Make another model. Explain which model you think is better.
Answer:

Topic 4 Fluency Practice Activity

Point & Tally
Find a partner. Get paper and a pencil. Each partner chooses a different color: light blue or dark blue.
Partner I and Partner 2 each point to a black number at the same time. Both partners add those numbers.
If the answer is on your color, you get a tally mark. Work until one partner gets twelve tally marks.

I can … add within 20.
Envision Math Common Core Grade 2 Answer Key Topic 4 Fluently Add Within 100 69

Topic 4 Vocabulary Review

Understand Vocabulary
Word List

  • addends
  • compatible numbers
  • ones
  • partial sum
  • regroup
  • sum
  • tens

Use the problem at the right. Write partial sum or sum for each.
Envision Math Common Core Grade 2 Answer Key Topic 4 Fluently Add Within 100 70
Question 1.
70 is a _________ .
Answer:
70 is a partial sum.

Explanation:
Here, the number 70 is a partial sum, because partial sum is just a sum of part of sequence.

Question 2.
17 is a ___________.
Answer:
17 is a partial sum.

Explanation:
Here, the number 17 is a partial sum, because partial sum is just a sum of part of sequence.

Question 3.
87 is the __________.
Answer:
87 is a sum.

Explanation:
Here, the number 87 is a sum, because it is the result of the addition.

Question 4.
Use the ones column in the problem at the right. Which compatible numbers can you add to make a ten two different ways?
Envision Math Common Core Grade 2 Answers Topic 4 Fluently Add Within 100 71
Write two different equations.
Answer:
8 + 2 = 10,
6 + 4 = 10.

Explanation:
The two different equations which are compatible numbers can we add to make a ten is
8 + 2 = 10,
6 + 4 = 10.

Use Vocabulary in Writing
Question 5.
Solve 27 + 35 by breaking apart both addends. Tell how you solved the problem. Use terms from the Word List.
Answer:
27 + 35 = 65.

Explanation:
Here, we have added the ones and then we will regroup and added to find the sum.
27 + 35 = 65.

Topic 4 Reteaching

Set A

Find 55 + 17. Use place-value blocks. Show the addends. Join the tens and ones. Regroup if needed.
Envision Math Common Core Grade 2 Answers Topic 4 Fluently Add Within 100 72

Add. Use place-value blocks to show your work. Regroup if needed.
Question 1.
36 + 23 = ________
Envision Math Common Core Grade 2 Answers Topic 4 Fluently Add Within 100 73

Answer:
The sum of 36 + 23 is 59 which is 5 tens and 9 ones.

Explanation:
The sum of 36 + 23 is
30 + 20 = 50
6 + 3 = 9
50 + 9 = 59.

Question 2.
19 + 44 = _______
Envision Math Common Core Grade 2 Answers Topic 4 Fluently Add Within 100 74
_______ tens _______ ones
Answer:
The sum of 19 + 44 is  63 which is 6 tens and 3 ones.

Explanation:
The sum of 19 + 44 is
10 + 40 = 50
9 + 4 = 13
50 + 13 = 63.

Set B

Find 24 + 49. Draw place-value blocks to show the addends. Join the tens and ones. Regroup if needed.
Envision Math Common Core Grade 2 Answers Topic 4 Fluently Add Within 100 75

Add. Use place value and draw blocks.
Question 3.
64 + 13 = _______
Answer:
The sum of 64 + 13 is 77 which is 7 tens and 7 ones.

Explanation:
The sum of 64 + 13 is
60 + 10 = 70
4 + 3 = 7
70 + 7 = 77.

Question 4.
27 + 56 = ________
Answer:
The sum of 23 + 56 is 79 which is 7 tens and 9 ones.

Explanation:
The sum of 23 + 56 is
20 + 50 = 70
3 + 6 = 9
70 + 9 = 79.

Set C

You can draw blocks and use partial sums to find 46 + 37.
Envision Math Common Core Grade 2 Answers Topic 4 Fluently Add Within 100 76

Add. Draw place-value blocks and use partial sums.
Question 5.
33 + 57
Drawings:
Envision Math Common Core Grade 2 Answers Topic 4 Fluently Add Within 100 77
Answer:
The partial sum of 33 + 57 is 90.

Explanation:
Given that 33 + 57, the partial sum of 33 + 57 is
Envision-Math-Common-Core-Grade-2-Answers-Topic-4-Fluently-Add-Within-100-77-1

Set D

Find 29 + 63. You can break apart the addends and use partial sums.
Envision Math Common Core Grade 2 Answers Topic 4 Fluently Add Within 100 78

Add. Break apart the addends and use partial sums.
Question 6.
Envision Math Common Core Grade 2 Answers Topic 4 Fluently Add Within 100 79
Answer:
The partial sum of 17 + 77 is 94.

Explanation:
Given that 17 + 77, the partial sum of 17 + 77 is
Envision-Math-Common-Core-Grade-2-Answers-Topic-4-Fluently-Add-Within-100-79-1

Question 7.
Envision Math Common Core Grade 2 Answers Topic 4 Fluently Add Within 100 80
Answer:
The partial sum of 24 + 38 is 62.

Explanation:
Given that 24 + 38, the partial sum of 24 + 38 is
Envision-Math-Common-Core-Grade-2-Answers-Topic-4-Fluently-Add-Within-100-80-1

Set E

Find 32 + 19. Break apart the second addend and add mentally.
Envision Math Common Core Grade 2 Answers Topic 4 Fluently Add Within 100 81

Break apart the second addend to add. Show your work.
Question 8.
Envision Math Common Core Grade 2 Answers Topic 4 Fluently Add Within 100 82
Answer:
The sum of 24 + 55 is 79.

Explanation:
The sum of 24 + 55 is 79.
Envision-Math-Common-Core-Grade-2-Answers-Topic-4-Fluently-Add-Within-100-82-1

Question 9.
Envision Math Common Core Grade 2 Answers Topic 4 Fluently Add Within 100 83
Answer:
The sum of 64 + 27 is 91.

Explanation:
The sum of 64 + 27 is 91.
Envision-Math-Common-Core-Grade-2-Answers-Topic-4-Fluently-Add-Within-100-83-1

Set F

Use partial sums to find 65 + 7 + 13.
Envision Math Common Core Grade 2 Answers Topic 4 Fluently Add Within 100 84

Add using partial sums.
Question 10.
Envision Math Common Core Grade 2 Answers Topic 4 Fluently Add Within 100 85
Answer:
The partial sum is 70.

Explanation:
Given that 22 + 21 + 9 + 18, the partial sum of 22 + 21 + 9 + 18 is
Envision-Math-Common-Core-Grade-2-Answers-Topic-4-Fluently-Add-Within-100-85-1

Question 11.
Envision Math Common Core Grade 2 Answers Topic 4 Fluently Add Within 100 86
Answer:
The partial sum of 41 + 15 + 29 + 10 is 95.

Explanation:
Given that 41 + 15 + 29 + 10, the partial sum of 41 + 15 + 29 + 10 is
Envision-Math-Common-Core-Grade-2-Answers-Topic-4-Fluently-Add-Within-100-86-1

Set G

27 students are eating lunch. More students join them. Now 63 students are eating lunch. How many students joined them?
Write an equation: 27 + ? = 63 Count on to find the missing addend:
Envision Math Common Core Grade 2 Answers Topic 4 Fluently Add Within 100 87
So, 36 students joined them.

Complete the bar diagram, write an equation, and solve.
Question 12.
Lana has 24 crayons. Then she gets some more crayons. Now she has 42 crayons. How many crayons does Lana get?
Envision Math Common Core Grade 2 Answers Topic 4 Fluently Add Within 100 88
Answer:
The number of crayons does Lana gets is 66 crayons.

Explanation:
Given that Lana has 24 crayons and then she gets some more crayons and now she has 42 crayons. So the number of crayons does Lana gets is 24 + 42 which is 66 crayons.
Envision-Math-Common-Core-Grade-2-Answers-Topic-4-Fluently-Add-Within-100-88-1

Set H

Thinking Habits
Model with Math
Can I use a drawing, diagram, table, graph, or objects to show the problem?
Can I write an equation to show the problem?
Envision Math Common Core Grade 2 Answers Topic 4 Fluently Add Within 100 89

Make a model and solve the problem.
Question 13.
Students ride buses to the museum. 28 students ride in Bus A. 27 students ride in Bus B. How many students ride in both buses?
Answer:
The total number of students ride in both buses is 55 students.

Explanation:
Given that 28 students ride in Bus A and 27 students ride in Bus B. So the total number of students ride in both buses is 28 + 27 which is 55 students.

Topic 4 Assessment Practice

Question 1.
Kelly has 46 beads. Her sister gives her 28 more beads. How many beads does Kelly have now?
A. 18
B. 64
C. 22
D. 74
Answer:
The total number of beads does Kelly have now is 74 beads.

Explanation:
Given that Kelly has 46 beads and her sister gives her 28 more beads. So the total number of beads does Kelly have now is 46 + 28 which is 74 beads.

Question 2.
Which are equal to 45 + 38? Choose all that apply.
☐ 40 + 30 + 5+ 8
☐ 93
☐ 45 + 30 + 5 + 3
☐ 40 + 30 + 10
☐ 83
Answer:
Option A and Option E.

Explanation:
Given that 45 + 38, so 45 + 38 is equal to 40 + 30 + 5 + 8 which is 83.

Question 3.
Is the sum equal to 81? Choose Yes or No.
Envision Math Common Core Grade 2 Answers Topic 4 Fluently Add Within 100 90
Answer:
Option B and Option D.

Explanation:
Given that the sum equal to 81, so the addends will be 52  + 29 and 63 + 18 which is 81.
Envision-Math-Common-Core-Grade-2-Answers-Topic-4-Fluently-Add-Within-100-90-1

Question 4.
Find 27 + 44 using partial sums. Show how you solved the problem.
Answer:
The sum of 27 + 44 is 71.

Explanation:
The partial sum of 27 + 44 is
= 27 + 40 + 4
= 67 + 4
= 71.

Question 5.
Which is the sum of 57 + 15?
Envision Math Common Core Grade 2 Answers Topic 4 Fluently Add Within 100 91
A. 82
B. 72
C. 62
D. 42
Answer:
Option B.

Explanation:
The sum of 57 + 15 is 72.

Question 6.
Which are the same amount as 13 + 8 + 7? Choose all that apply.
☐ 20 + 8
☐ 10 + 10 + 8
☐ 18
☐ 28
☐ 20 + 7
Answer:
Option A, Option B and Option D.

Explanation:
The same amount as 13 + 8 + 7 is 20 + 8, 10 + 10 + 8 and 28.

Question 7.
What is the sum of 26 + 53 + 7? Show your work.
26 + 53 + 7 = ________
Answer:
The sum is 86.

Explanation:
The sum of 26 + 53 + 7 is
= 79 + 7
=  86.

Question 8.
Find the sum of 23 and 19. Then subtract 10 from that sum. Show and explain your work.
The answer is __________
Answer:
The answer is 32.

Explanation:
Given that the sum of 23 and 19 is 42 and should subtract 10 from the sum which is 42 – 10 = 32.

Question 9.
A. Find the sum. Use a strategy. Show your work.
25 + 37 + 15 + 8 = __________
Answer:
25 + 37 + 15 + 8 = 85.

Explanation:
The sum of 25 + 37 + 15 + 8 is
= 25 + 60
= 85.

B. Explain how you found the sum and why your strategy works.
Answer:
Here, we will first add ones and got 25 and then we will regroup the 2 tens and then we will add to get the sum of 85.

Question 10.
Ms. Wise has 12 tablets. Then she gets 9 more tablets. Ms. Wise has 20 students in her class. She gives each student one tablet. How many tablets does she have left? Use equations to solve the problem.
________ tablet(s)
Answer:
The number of tablets left with Ms. Wise is 1 tablet.

Explanation:
Given that Ms. Wise has 12 tablets and she gets 9 more tablets, so the total tablets will be 12 + 9 which is 21 tablets. Ms. Wise has 20 students in her class and she gives each student one tablet. So the number of tablets left with Ms. Wise is 21 – 20 which is 1 tablet.

Question 11.
What is the sum of 59 + 33?
Draw place-value blocks and show your work in the blue box at the right.
59 + 33 = _________
Answer:

Question 12.
Each equation has a missing addend. Find it in the number cards. Draw lines to match. Then write the missing addend in the gray box.
Envision Math Common Core Grade 2 Answers Topic 4 Fluently Add Within 100 92
Answer:
The missing addends are 7, 8, 5, 6.

Explanation:
Given that 6 + 14 +– + 3 = 30, so the missing addend is 23 + — = 30 and the missing addend is 30 -23 = 7.
Given that 3 + 32 + 7 +– = 50, so the missing addend is 42+ — = 50 and the missing addend is 50 – 42= 8.
Given that 25 + 25  +– + 5 = 60, so the missing addend is 55 + — = 60 and the missing addend is 60 – 55 = 5.
Given that 5 +– + 15 + 14 = 40, so the missing addend is 34 + — = 40 and the missing addend is 40 – 34 = 6.

Envision-Math-Common-Core-Grade-2-Answers-Topic-4-Fluently-Add-Within-100-92-1

Question 13.
Corey has 17 more marbles than Tony. Tony has 64 marbles. How many marbles does Corey have?
Envision Math Common Core Grade 2 Answers Topic 4 Fluently Add Within 100 93
Use the bar diagram to model and solve the problem. Show your work.
_________ marbles
Answer:
The total number of marbles is 81 marbles.

Explanation:
Given that Corey has 17 more marbles than Tony and Tony has 64 marbles. So the total number of marbles is 17 + 64 which is 81 marbles.

Topic 4 Performance Task

Our Pets
Students draw pictures of their pets. The chart shows the number of pets the students have.
Envision Math Common Core Grade 2 Answers Topic 4 Fluently Add Within 100 94
Question 1.
How many dogs and cats do the students have? Show your work.
_________ dogs and cats
Answer:
&0 students have dogs and cats.

Explanation:
The total number of dogs and cats is 41 + 29 which is 70 students.

Question 2.
How many cats and fish do the students have? Show your work.
__________ cats and fish
Answer:
53 students have cats and fish

Explanation:
The total number of cats and fish is 29 + 24 which is 53 students.

Question 3.
Use partial sums to find how many cats, rabbits, and fish the students have. Be sure to check your work.
Envision Math Common Core Grade 2 Answers Topic 4 Fluently Add Within 100 95
How many cats, rabbits, and fish in all?
__________ cats, rabbits, and fish
Answer:
59 students have cats, rabbits, and fish.

Explanation:
The total number of cats, rabbits, and fish is 29 + 6 + 24 which is 59 students.
Envision-Math-Common-Core-Grade-2-Answers-Topic-4-Fluently-Add-Within-100-95-1

Question 4.
Explain how to use partial sums to add.
Answer:

Question 5.
The students also draw pictures of 10 hamsters, 19 birds, and 5 mice.
Part A
Complete the model to show how to find the total number of hamsters, birds, and mice.
Envision Math Common Core Grade 2 Answers Topic 4 Fluently Add Within 100 96
Answer:

Part B
Complete the equation to show how many hamsters, birds, and mice they draw. Then write the total.
Envision Math Common Core Grade 2 Answers Topic 4 Fluently Add Within 100 97
__________ hamsters, birds, and mice
Answer:

enVision Math Common Core Grade 2 Answer Key

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