1 7 Multiplying and Dividing Integers Warm Up

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

1 -7 Multiplying and Dividing Integers 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 2 – 9 – 1 5 8 – 3

1 -7 Multiplying and Dividing Integers Learn to multiply and divide integers.

1 -7 Multiplying and Dividing Integers A positive number multiplied by an integer can be written as repeated addition. 3(– 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.

1 -7 Multiplying and Dividing Integers 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) = – 600 2(– 200) = – 400 1(– 200) = – 200 0(– 200) = 0 + 200 – 1(– 200) = 200 The product of two negative – 2(– 200) = 400 integers is a positive – 3(– 200) = 600 integer.

1 -7 Multiplying and Dividing Integers

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

1 -7 Multiplying and Dividing Integers Additional Example 1: Multiplying and Dividing Integers Multiply or divide. C. – 18 2 – 9 D. Signs are different. Answer is negative. – 25 – 5 Signs are the same. 5 Answer is positive.

1 -7 Multiplying and Dividing Integers Check It Out: Example 1 Multiply or divide. A. 5(– 2) Signs are different. – 10 Answer is negative. B. – 3(– 2) 6 Signs are the same. Answer is positive.

1 -7 Multiplying and Dividing Integers Check It Out: Example 1 Multiply or divide. C. – 24 3 – 8 D. Signs are different. Answer is negative. – 12 – 2 Signs are the same. 6 Answer is positive.

1 -7 Multiplying and Dividing Integers 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.

1 -7 Multiplying and Dividing Integers 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.

1 -7 Multiplying and Dividing Integers 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.

1 -7 Multiplying and Dividing Integers 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.

1 -7 Multiplying and Dividing Integers 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.

1 -7 Multiplying and Dividing Integers 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.

1 -7 Multiplying and Dividing Integers Lesson Quizzes Standard Lesson Quiz for Student Response Systems

1 -7 Multiplying and Dividing Integers 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

1 -7 Multiplying and Dividing Integers Lesson Quiz for Student Response Systems 1. Multiply – 9(6). A. 54 B. 45 C. – 45 D. – 54

1 -7 Multiplying and Dividing Integers Lesson Quiz for Student Response Systems – 19(4) 2. Multiply or divide. – 4 A. – 19 B. 19 C. 30 D. 36

1 -7 Multiplying and Dividing Integers Lesson Quiz for Student Response Systems 3. Simplify – 7(17 – 6). A. – 77 B. – 66 C. 66 D. 77

1 -7 Multiplying and Dividing Integers Lesson Quiz for Student Response Systems 4. Simplify 9(– 6 – 1). A. 63 B. 54 C. – 63 D. – 64

1 -7 Multiplying and Dividing Integers 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