Section 1.6 Section 1.6

Multiplying & Dividing Integers

ObjectivesObjectives

NS1.2 Add, subtract, multiply, and divide rational numbers (integers, fractions, and terminating decimals) and

take positive rational numbers to whole-number powers.

California Standards

MultiplyingMultiplying & & Dividing Dividing Two IntegersTwo Integers

1. Same signs = positive

2. Different signs = negative

2 Simple Rules2 Simple Rules

Examples Examples

4(3)

5(-2)

(-4)(-6)

(-3)²

Both signs are positive so answer is

positive = 12

Different signs, so answer will be

negative-- = -10Same signs, so answer will be

positive = 24

-3 times -3, so same signs mean

positive answer = 9

Simplifying Expressions Using Multiplication

-8 (-y) =● 10 (-a)● (-11)(-w)

Remember: the dot and parentheses next to a number or letter means to multiply.

8y

Because a negative times a negative equals a positive, your answer is positive

-10a 11w

Here, negative times a positive equals a negative

Let’s practice…Let’s practice…

A. –6(4)

B. –8(–5)(2)

40(2)

–24

Multiply or divide.

–8(–5)(2)

80

C.

–9

–182

D.

5

–25–5

Let’s practice…Let’s practice…

A. 3(–6 – 12)

–54

3(–18)

B. –5(–5 + 2)

15

–5(–3)3(–6 + –12)

Sports ApplicationSports Application

A golfer plays 5 holes. On 3 holes, he is 4 strokes over par. On 2 holes, he is 4 strokes 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(–4)

4

12 + (–8)

The golfer's score was 4 over par.

Check It Out!Check It Out!

A. -3(-2)(4)24

B. -3(6) - 9

- 27

-18 - 9

Sports ApplicationSports Application

3(3) + 4(–3)

–3

9 + (–12)

A golfer plays 7 holes. On 3 holes, he has a gain of 3 strokes. On 4 holes, he is 3 strokes 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.

The golfer's score was 3 under par.

try these!try these!

4 ( -6) -9 -8● -5(2)= -24 = 72 -10

42

-7

-16

2

-3

-3= -6 = -8 =1

x = 5 y = -8

9x

-5x²y

-yx9(5)

-5

45

-5-9

5²(-8)

25(-8)-200

-(-8)540

Lesson QuizLesson Quiz

1. –8(4) 2.–32 6–12(5)

–10

3. –2(13 – 4) 4. 6(–5 – 3)–18 –48

5. Devin 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

SUMMARY

Rules for multiplying and dividing integers….