Section 1 6 Multiplying Dividing Integers Objectives California

Section 1. 6 Multiplying & Dividing Integers

Objectives California Standards NS 1. 2 Add, subtract, multiply, and divide rational numbers (integers, fractions, and terminating decimals) and take positive rational numbers to whole-number powers.

2 Simple Rules Multiplying & Dividing Two Integers 1. Same signs = positive 2. Different signs = negative

Examples 4(3) 5(-2) Both signs are positive so answer is positive = 12 Different signs, so answer will be negative -- = -10 (-4)(-6) (-3)² Same signs, so answer will be positive = 24 -3 times -3, so same signs mean positive answer = 9

Simplifying Expressions Using Multiplication -8 ● (-y) = 8 y 10 ● (-a) -10 a Because a negative times a negative equals a positive, your answer is positive (-11)(-w) 11 w Here, negative times a positive equals a negative Remember: the dot and parentheses next to a number or letter means to multiply.

Let’s practice… Multiply or divide. A. – 6(4) C. – 24 B. – 8(– 5)(2) 40(2) 80 – 18 2 – 9 D. – 25 – 5 5

Sports 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) 12 + (– 8) 4 The golfer's score was 4 over par.

Check It Out! A. -3(-2)(4) 24 B. -3(6) - 9 -18 - 9 - 27

Sports Application 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. 3(3) + 4(– 3) 9 + (– 12) – 3 The golfer's score was 3 under par.

try these! 4 ( -6) -9 -8 ● = -24 = 72 -5(2) -10 42 -16 -3 -7 = -6 2 x=5 9 x 9(5) 45 -5 -9 = -8 -3 =1 y = -8 x²y 5²(-8) 25(-8) -200 -yx -(-8)5 40

Lesson Quiz 1. – 8(4) – 32 3. – 2(13 – 4) – 18 2. – 12(5) – 10 6 4. 6(– 5 – 3) – 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….