1. Warm Up
Multiply or divide.
1. 5(8)‏ 40
2. 6(12)‏ 72 36 9 49 7 3. 4 4. 7
192 16 12
5. 18(7)‏
126 6.

2. Problem of the Day
Complete the pyramid by filling in the missing numbers. Each number is the sum of the numbers in the two boxes below it. –4 –8 4 –7 –1 5 8 –9 2 –3

3. Learn to multiply and divide integers.

4. A positive number multiplied by an integer can be written as repeated addition.
3(–200) = –200 + (–200) + (–200) = –600
From what you know about adding and subtracting integers, you can see that a positive integer times a negative integer is negative.

5. You know that multiplying two positive integers together gives you a positive answer. Look for a pattern in the integer multiplication at right to understand the rules for multiplying two negative integers.
3(–200) =
2(–200) =
1(–200) =
0(–200) =
–1(–200) =
–2(–200) =
–3(–200) =
–600
+ 200
–400
+ 200
–200
+ 200
The product of two negative integers is a positive integer.
200
400
600

7. Additional Example 1: Multiplying and Dividing Integers
Multiply or divide.
A. –6(4)‏
Signs are different.
–24
Answer is negative.
B. –8(–5)‏
Signs are the same. 40
Answer is positive.

8. Additional Example 1: Multiplying and Dividing Integers
Multiply or divide.
–18 2 C.
Signs are different. –9
Answer is negative.
–25 –5 D.
Signs are the same. 5
Answer is positive.

9. Check It Out: Example 1
Multiply or divide.
A. 5(–2)‏
Signs are different.
–10
Answer is negative.
B. –3(–2)‏
Signs are the same. 6
Answer is positive.

10. Check It Out: Example 1
Multiply or divide.
–24 3 C.
Signs are different. –8
Answer is negative.
–12 –2 D.
Signs are the same. 6
Answer is positive.

11. Additional Example 2: Using the Order of Operations with Integers
Simplify.
A. 3(–6 – 12)‏
Subtract inside the parentheses.
3(–18)‏
Think: The signs are different.
–54
The answer is negative.
B. –5(–5 + 2)‏
Subtract inside the parentheses.
–5(–3)‏
Think: The signs are the same. 15
The answer is positive.

12. Additional Example 2: Using the Order of Operations with Integers
Simplify.
C. –2(14 – 5)‏
Subtract inside the parentheses.
–2(9)‏
Think: The signs are different.
–18
The answer is negative.

13. Check It Out: Example 2
Simplify.
A. 2(1 – 8)‏
Subtract inside the parentheses.
2(–7)‏
Think: The signs are different.
–14
The answer is negative.
B. 4(–3 – 8)‏
Subtract inside the parentheses.
4(–11)‏
Think: The signs are different.
–44
The answer is negative.

14. Check It Out: Example 2
Simplify.
C. –3(6 – 9)‏
Subtract inside the parentheses.
–3(–3)‏
Think: The signs are the same. 9
The answer is positive.

15. Additional Example 3: Sports Application
A golfer plays 5 holes. On 3 holes, he is 4 strokes over par. On 2 holes, he is 1 stroke under par. Each score over par can be represented by a positive integer, and each score under par can be represented by a negative integer. Find the total score relative to par.
3(4) + 2(–1)‏
Add the losses to the gains.
12 + (–2)‏
Multiply. 10
Add.
The total score is 10 strokes over par.

16. Check It Out: Example 3
A golfer plays 9 holes. On 3 holes, he is 3 strokes over par. On 4 holes, he is 3 stroke under par. Each score over par can be represented by a positive integer, and each score under par can be represented by a negative integer. Find the total score relative to par.
3(3) + 4(–3)‏
Add the losses to the gains.
9 + (–12)‏
Multiply. –3
Add.
The total score is 3 strokes under par.

17. Lesson Quizzes
Standard Lesson Quiz
Lesson Quiz for Student Response Systems

18. Lesson Quiz
Multiply or divide.
1. –8(4)‏
–32 2.
–12(5)‏
–10 6
Simplify.
3. –2(13 – 4)‏
–18
4. 6(–5 – 3)‏
–48
5. Evin completes 11 transactions in his bank account. In 6 transactions, he withdraws $10. In 5 transactions, he deposits $20. Find the total net change in dollars.
$40

19. Lesson Quiz for Student Response Systems
1. Multiply –9(6).
A. 54
B. 45
C. –45
D. –54

20. Lesson Quiz for Student Response Systems
–19(4) –4
2. Multiply or divide
A. –19
B. 19
C. 30
D. 36

21. Lesson Quiz for Student Response Systems
3. Simplify –7(17 – 6).
A. –77
B. –66
C. 66
D. 77

22. Lesson Quiz for Student Response Systems
4. Simplify 9(–6 – 1).
A. 63
B. 54
C. –63
D. –64

23. Lesson Quiz for Student Response Systems
5. Hannah makes 14 trips to her mom’s home. On 8 of her trips, she gives her mom $25 for safekeeping. On her other 6 trips, she takes $30 from her mom. How much of Hannah’s money is left with her mom?
A. $10
B. $20
C. $30
D. $40