2. Key Concept: Multiply Integers with Different Signs
Main Idea
Key Concept: Multiply Integers with Different Signs
Example 1: Multiply Integers with Different Signs
Example 2: Multiply Integers with Different Signs
Key Concept: Multiply Integers with the Same Sign
Example 3: Multiply Integers with the Same Sign
Example 4: Multiply Integers with the Same Sign
Example 5: Multiply Integers with the Same Sign
Example 6: Real-World Example
Example 7: Add Integers with the Same Sign
Lesson Menu

3. Use the rules for multiplying integers.
Main Idea/Vocabulary

4. Key Concept

5. Multiply Integers with Different Signs
Find 5(–4).
5(–4) = –20 The integers have different signs. The product is negative.
Answer: –20
Example 1

6. Find 2(–7).
A. –14
B. –9
C. –5
D. 14
Example 1 CYP

7. Multiply Integers with Different Signs
Find –3(9).
–3(9) = –27 The integers have different signs. The product is negative.
Answer: –27
Example 2

8. Find –2(11).
A. 22
B. 13
C. –13
D. –22
Example 2 CYP

9. Key Concept 3

10. Multiply Integers with the Same Sign
Find –6(–8).
–6(–8) = 48 The integers have the same sign. The product is positive.
Answer: 48
Example 3

11. Find –4(–1).
A. 4
B. 3
C. –4
D. –5
Example 3 CYP

12. Multiply Integers with the Same Sign
Find (–8)2.
(–8)2 = (–8)(–8) There are two factors of –8.
= 64 The product is positive.
Answer: 64
Example 4

13. Find (–1)2.
A. –2
B. –1
C. 1
D. 2
Example 4 CYP

14. Multiply Integers with the Same Sign
Find –2(–5)(–6).
–2(–5)(–6) = [–2(–5)](–6)] Associative Property
= 10(–6) –2(–5) = 10
= –60 10(–6) = –60
Answer: –60
Example 5

15. Find –6(–7)(–2).
A. –84
B. –26
C. 54
D. 84
Example 5 CYP

16. Answer: –1,500 feet or 1,500 feet below Earth’s surface
MINES A mine elevator descends at a rate of 300 feet per minute. How far below Earth’s surface will the elevator be after 5 minutes?
If the elevator descends 300 feet per minute then after 5 minutes the mine elevator will be at 5(–300) or –1,500 feet. The mine elevator will descend to 1,500 feet below the Earth’s surface.
Answer: –1,500 feet or 1,500 feet below Earth’s surface
Example 6

17. FOOD John’s freezer decreases the temperature of a casserole by 3ºF every minute. What is the change in temperature after 10 minutes?
A. +30ºF
B. +13ºF
C. –13ºF
D. –30ºF
Example 6 CYP

18. Evaluating Expressions
ALGEBRA Evaluate abc if a = –3, b = 5, and c = –8.
abc = –3(5)(–8) Replace a with –3, b with 5, and c with –8.
= (–15)(–8) Multiply –3 and 5.
= 120 Multiply –15 and –8.
Answer: The solution is 120.
Example 7

19. ALGEBRA Evaluate rst if r = –1, s = 2, and t = –6.
C. 11
D. 12
Example 7 CYP