## Envision Math 5th Grade Textbook Answer Key Topic 18.1 Ordered Pairs

Review What You Know

Vocabulary
Choose the best term from the box. Question 1.
(2, 5) is an example of a(n) ? .

Question 2.
If you name a point (4, 6), 4 is the ? and 6 is the ? .

Question 3.
A coordinate plane is made up of two intersecting ? .

Basic Facts
Find each sum, difference, or product,
Question 4.
4 × 5

Question 5.
7 × 8

Question 6.
3 × 6

Question 7.
8 + 6

Question 8.
3 + 9

Question 9.
5 + 7

Question 10.
16 – 9

Question 11.
8 – 6

Question 12.
12 – 8

Algebra
Question 13.
Evaluate 4x + 8 for x = 7

Question 14.
Evaluate 51 ÷ y – 2 for y = 3

Graphing Ordered Pairs
Writing to Explain Write an answer for the question.
Question 15.
Explain the steps you would follow to graph Point A (2, 3) on a coordinate grid .

Ordered Pairs

How can you locate points on a coordinate grid? A coordinate grid makes it easy to locate a point on a map. Start at 0. Go 3 blocks east and then 2 blocks north. You will be at the bank.
An ordered pair names a point on a coordinate grid. The bank is at (3, 2)

Another Example
How do you graph a point on a coordinate plane?
You know that graphs represent data. Now you will see how ordered pairs of numbers can represent points on a coordinate plane.
Graph Point R at (-4, -5) Step 1: Draw and label the x-axis and y-axis on grid paper.
Step 2: Move 4 units to the left of the origin.Then, move 5 units down.
Step 3: Mark a point and label it R.

Explain It
Question 1.
How would you locate the point (+4, -5) on a coordinate grid?

Question 2.
If the location of point R above were changed to (-4, +5), would the point be above or below its current position?

Question 3.
Suppose you want to graph the point (0, +5) on graph paper. When you start from the origin, do you move right 0 units or move up 0 units?

A coordinate plane extends to include both positive and negative numbers. It has a horizontal x-axis and a vertical y-axis. The point at which the x-axis and y-axis intersect is called the origin. The first number in an ordered pair, the x-coordinate, names the distance to the right or left from the origin along the x-axis. The second number, the y-coordinate, names the distance up or down from the origin along the y-axis. The ordered pair for Point A is (-2, 3).

Guided Practice

Do you know HOW?
In 1 through 4, write the ordered pair for each point. Use the grid at the right. Question 1.
A

Question 2.
B

Question 3.
C

Question 4.
D

Do you UNDERSTAND?
Question 5.
Writing to Explain Describe how to plot the ordered pair (-3, +4).

Question 6.
What ordered pair names the origin of any coordinate plane?

Question 7.
In the example above, name the ordered pair for a point that is 3 units directly above Point A.

Independent Practice

In 8 through 13, write the ordered pair for each point. Use the grid at the right. Question 8.
M

Question 9.
N

Question 10.
P

Question 11.
R

Question 12.
S

Question 13.
T

In 14 through 19, graph and label each point on a grid.
Question 14.
H (2, +1)

Question 15.
J (+5, +1)

Question 16.
K(0, +5)

Question 17.
E (+1, -3)

Question 18.
F (+4, -5)

Question 19.
G (-3, -4)

Problem Solving

Geometry For 20 through 24, complete the table by listing the ordered pair for each vertex of the pentagon at the right. Question 25.
Algebra Which equation shows the relationship of the values in the table? A. y = x + 3
B. x = y – 3
C. y = x – 3
D. y = x

Question 26.
A chessboard is similar to a coordinate grid. The pieces that look like horses are called knights. What letter-number combinations name the locations of the white knights? Question 27.
Writing to Explain
The streets in many cities in the United States are laid out in a coordinate grid. How is this helpful when finding locations in cities such as Los Angeles, California?

Question 28.
In a class of 25 students, 15 are girls. Which does NOT show the part of the class that are girls?
A. $$\frac{3}{5}$$
B. 0.6
C. 60%
D. 0.3

Stop and Practice

Find each difference.
Question 1.
6.7 – 0.921

Question 2.
219.2 – 61.3

Question 3.
2.5 – 1.054

Question 4.
88.7 – 17.62

Question 5.
1.17 – 0.362

Question 6.
1.1 – 0.033

In 7 through 13, solve each equation for c.
Question 7.
$$\frac{c}{8}$$ = 9

Question 8.
$$\frac{c}{16}$$ = 2

Question 9.
$$\frac{c}{17}$$ = 5

Question 10.
$$\frac{c}{2}$$ = 2

Question 11.
$$\frac{c}{30}$$ = 3

Question 12.
$$\frac{c}{10}$$ = 13

Question 13.
$$\frac{c}{7}$$ = 6

Find each difference. Estimate to check if the answer is reasonable.
Question 14. Question 15.
734 ÷ 6

Question 16. Question 17.
723 ÷ 9

Question 18.
10,648 ÷ 39

Question 19. Question 20. Question 21.
6,203 ÷ 43

Error Search Find each sum or difference that is not correct. Write it correctly and explain the error.
Question 22. Question 23. Question 24. Question 25. Question 26. Number Sense
Estimating and Reasoning Write whether each statement is true or false. Explain your reasoning.
Question 27.
The sum of -8 and +12 equals -4.

Question 28.
The quotient of 5,763 ÷ 8 is between 700 and 800.

Question 29.
The difference of 25,980 – 15,980 is less than 10,000.
The sum of 5$$\frac{7}{10}$$ and 3$$\frac{3}{4}$$ is greater than 9.