1. Warm Up
Add.
1. – –6 + (–28)
2. –12 + (–9) (–87)
(–19) 6. –18 + (–24) –5
–34
–21 17 13
–42

2. Subtracting an integer is the same as adding its opposite.
Subtracting a lesser number from a greater number is the same as finding how far apart the two numbers are on a number line.
Subtracting an integer is the same as adding its opposite.

3. Example 1: Subtracting Integers
–7 – 4 = –7 + (–4)
= –11
B. 8 – (–5)
8 – (–5) = 8 + 5
= 13
C. –6 – (–3)
–6 – (–3) = –6 + 3
= –3

4. Check It Out: Example 1
Subtract.
A. 3 – (–6)
3 – (–6) = 3 + 6
= 9
B. –4 – 1
–4 – 1 = –4 + (–1)
= –5
C. –7 – (–8)
–7 – (–8) = –7 + 8
= 1

5. Example 2: Evaluating Expressions with Integers
Evaluate the expression for the given value of the variable.
A. 8 – j for j = –6
c. n – 6 for n = –2
n – 6
8 – j
B. –9 – y for y = –4
–2 – 6
8 – (–6)
–9 – y
–2 + (–6)
8 + 6
–9 – (–4) –8 14
–9 + 4 –5

6. Example 3: Architecture Application
The top of the Sears Tower in Chicago, is feet above street level, while the lowest level is 43 feet below street level. How far is it from the lowest level to the top?
Subtract the lowest level from the height.
1454 – (–43)
Add the opposite of (–43).
Same sign; use the sign of the integers.
1497
It is 1497 feet from the lowest level to the top.

7. Check It Out: Example 3
The distance from the high dive to the swimming pool is 10 feet. The pool is 12 feet deep. What is the total distance from the high dive to the bottom of the pool?
Subtract the depth of the pool from the height of the high dive.
10 – (–12)
Add the opposite of (–12).
Same sign; use the sign of the integers. 22
It is 22 feet from the diving board to the bottom of the pool.

8. Lesson Quiz
Subtract.
1. –6 – (–4) –2
2. –3 – 3 –6
3. 4 – (–5) 9
Evaluate each expression for the given value of the variable.
4. 9 – s for s = –5 14
5. –4 – w + 5 for w = 21
–20
6. Suretta is flying in an airplane and rises an additional 20 feet. Then she descends 190 feet toward the ground. How far below her original height did Suretta go?
170 feet