## 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) ? .

Answer:

Question 2.

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

Answer:

Question 3.

A coordinate plane is made up of two intersecting ? .

Answer:

**Basic Facts**

Find each sum, difference, or product,

Question 4.

4 × 5

Answer:

Question 5.

7 × 8

Answer:

Question 6.

3 × 6

Answer:

Question 7.

8 + 6

Answer:

Question 8.

3 + 9

Answer:

Question 9.

5 + 7

Answer:

Question 10.

16 – 9

Answer:

Question 11.

8 – 6

Answer:

Question 12.

12 – 8

Answer:

**Algebra**

Question 13.

Evaluate 4x + 8 for x = 7

Answer:

Question 14.

Evaluate 51 ÷ y – 2 for y = 3

Answer:

**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 .

Answer:

**Ordered Pairs**

How can you locate points on a coordinate grid?

Answer:

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?

Answer:

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?

Answer:

Question 2.

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

Answer:

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?

Answer:

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

Answer:

Question 2.

B

Answer:

Question 3.

C

Answer:

Question 4.

D

Answer:

**Do you UNDERSTAND?**

Question 5.

Writing to Explain Describe how to plot the ordered pair (-3, +4).

Answer:

Question 6.

What ordered pair names the origin of any coordinate plane?

Answer:

Question 7.

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

Answer:

**Independent Practice**

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

Question 8.

M

Answer:

Question 9.

N

Answer:

Question 10.

P

Answer:

Question 11.

R

Answer:

Question 12.

S

Answer:

Question 13.

T

Answer:

In 14 through 19, graph and label each point on a grid.

Question 14.

H (2, +1)

Answer:

Question 15.

J (+5, +1)

Answer:

Question 16.

K(0, +5)

Answer:

Question 17.

E (+1, -3)

Answer:

Question 18.

F (+4, -5)

Answer:

Question 19.

G (-3, -4)

Answer:

**Problem Solving**

Geometry For 20 through 24, complete the table by listing the ordered pair for each vertex of the pentagon at the right.

Answer:

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

Answer:

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?

Answer:

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?

Answer:

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

Answer:

**Stop and Practice**

Find each difference.

Question 1.

6.7 – 0.921

Answer:

Question 2.

219.2 – 61.3

Answer:

Question 3.

2.5 – 1.054

Answer:

Question 4.

88.7 – 17.62

Answer:

Question 5.

1.17 – 0.362

Answer:

Question 6.

1.1 – 0.033

Answer:

In 7 through 13, solve each equation for c.

Question 7.

\(\frac{c}{8}\) = 9

Answer:

Question 8.

\(\frac{c}{16}\) = 2

Answer:

Question 9.

\(\frac{c}{17}\) = 5

Answer:

Question 10.

\(\frac{c}{2}\) = 2

Answer:

Question 11.

\(\frac{c}{30}\) = 3

Answer:

Question 12.

\(\frac{c}{10}\) = 13

Answer:

Question 13.

\(\frac{c}{7}\) = 6

Answer:

Find each difference. Estimate to check if the answer is reasonable.

Question 14.

Answer:

Question 15.

734 ÷ 6

Answer:

Question 16.

Answer:

Question 17.

723 ÷ 9

Answer:

Question 18.

10,648 ÷ 39

Answer:

Question 19.

Answer:

Question 20.

Answer:

Question 21.

6,203 ÷ 43

Answer:

Error Search Find each sum or difference that is not correct. Write it correctly and explain the error.

Question 22.

Answer:

Question 23.

Answer:

Question 24.

Answer:

Question 25.

Answer:

Question 26.

Answer:

**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.

Answer:

Question 28.

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

Answer:

Question 29.

The difference of 25,980 – 15,980 is less than 10,000.

Answer:

Question 30.

The product of 8 and 5.943 is closer to 48 than 40.

Answer:

Question 31.

The sum of 5\(\frac{7}{10}\) and 3\(\frac{3}{4}\) is greater than 9.

Answer:

Question 32.

The k in the equation 13k = 39 is equal to 3.

Answer: