Adding Rational Numbers

Name_________________________________________________________

Date __________

Adding Rational Numbers

2.2

For use with Activity 2.2

Essential Question How can you use what you know about adding integers to add rational numbers? 1

ACTIVITY: Adding Rational Numbers

Work with a partner. Use a number line to find the sum. a. 2.7 + ( − 3.4)

−3

−2

−1

0

1

2

3

2.7 + ( − 3.4) = _________ b. 1.3 + ( −1.5)

−3

d. −1

−2

0

1

2

−3

3

1 3 + 4 4

−3

2

−1

c. − 2.1 + 0.8

−2

e.

−1

0

1

2

−2

0

1

2

3

0

1

2

3

3  3 + −  10  10 

−3

3

−1

−2

−1

ACTIVITY: Adding Rational Numbers

Work with a partner. Use a number line to find the sum. a. −1

2  4 + −  5  5

−3

−1

−2

−1

0

1

2

3

2  4 +  −  = _________ 5  5

Copyright © Big Ideas Learning, LLC All rights reserved.

Big Ideas Math Red Record and Practice Journal

29

Name ________________________________________________________ Date _________

2.2

Adding Rational Numbers (continued) b. −

7  7 +  −1  10  10 

−3

−2

−1

0

1

2

−3

3

d. − 0.4 + ( −1.9)

−3

3

−2

2  1 +  −1  3  3

c. −1

−2

−1

0

1

2

3

0

1

2

3

e. − 2.3 + ( − 0.6)

−1

0

1

2

−3

3

−2

−1

ACTIVITY: Writing Expressions

Work with a partner. Write the addition expression shown. Then find the sum. a.

Start at 0. Move 1.5 units to the right.

−4

b. Then move 3

−3

30

1.5

−1

7 units 10

right to end at

−4

−2

−3

0

Add 3

.

−2

−2

Big Ideas Math Red Record and Practice Journal

Then move 2.3 units left to end at −0.8.

Add −2.3.

1

7 . 10

3

Start at 0. Move 2

1 10

−1

2

1 10

units to the left. 0

1

2

3

Copyright © Big Ideas Learning, LLC All rights reserved.

Name_________________________________________________________

2.2

Date __________

Adding Rational Numbers (continued) c.

Then move 0.7 unit left to end at .

−4

−3

Start at 0. Move 1.1 units to the left.

Add −0.7. −1.1 −2

−1

0

1

2

3

What Is Your Answer? 4. IN YOUR OWN WORDS How can you use what you know about adding

integers to add rational numbers?

PUZZLE Find a path through the table so that the numbers add up to the

sum. You can move horizontally or vertically.

3 4

5. Sum:

Start

1 2 −

1 8

6. Sum: − 0.07

2 3 −

3 4

Copyright © Big Ideas Learning, LLC All rights reserved.

−

5 7

1 3

Start End

2.43

1.75

− 0.98

−1.09

3.47

− 4.88

Big Ideas Math Red Record and Practice Journal

End

31

Name _________________________________________________________ Date _________

2.2

Practice For use after Lesson 2.2

Add. Write fractions in simplest form.

 6  7

1. −

4 3 + 5 20

2. − 8 +  − 

4. −

1  5 + −  6  12 

5.

7. 0.46 + ( − 0.642)

10. Before a race, you start 4

9 + ( − 3) 10

8. 0.13 + ( − 5.7)

2  1 + −3  15  2 

3. 1

6. − 5

3  5 + −4  4  6

9. − 2.57 + ( − 3.48)

5 feet behind your friend. At the halfway point, 8

2 feet ahead of your friend. What is the change in distance 3 between you and your friend from the beginning of the race?

you are 3

32

Big Ideas Math Red Record and Practice Journal

Copyright © Big Ideas Learning, LLC All rights reserved.