On a 50-foot roll of cable, 15 ft are left. How many feet of

cable were used?

Adding and Subtracting Rational NumbersAdding and Subtracting Rational NumbersCOURSE 3 LESSON 4-4COURSE 3 LESSON 4-4

34

Let t = the amount used.

Words amount left + amount used = original amount

34Equation 15 + t = 50

4-4

(continued)

Adding and Subtracting Rational NumbersAdding and Subtracting Rational NumbersCOURSE 3 LESSON 4-4COURSE 3 LESSON 4-4

Subtract 15 from each side.t = 50 – 1534

34

The amount of cable used was 34 ft.14

4-4

15 + t = 5034

Rewrite 50 as 49 + , or 1. Subtract. t = 49 – 15 = 3444

34

44

14

Adding and Subtracting Rational NumbersAdding and Subtracting Rational Numbers

Find each sum or difference.

1. – 2. + 3. – 4. 4 – 1

5. It snowed 2 in. on top of 4 in. of snow already on the ground.

How deep is the snow now?

13

7 in.

COURSE 3 LESSON 4-4COURSE 3 LESSON 4-4

89

59

45

23

78

12

56

14

38

7 15

1 7 12

3

4-4

12

12