Multiplying and Dividing Integers 1-6 Multiplying and Dividing Integers Course 3 Warm Up Problem of the Day Lesson Presentation

Learn to multiply and divide integers.

Insert Lesson Title Here 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.

Insert Lesson Title Here 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

MULTIPLYING AND DIVIDING TWO INTEGERS Insert Lesson Title Here MULTIPLYING AND DIVIDING TWO INTEGERS If the signs are the same, the sign of the answer is positive. If the signs are different, the sign of the answer is negative.

Multiply or divide. A. –6(4) Signs are different. = –24 Answer is negative. B. –8(–5) Signs are the same. = 40 Answer is positive.

Multiply or divide. –18 2 C. Signs are different. = –9 Answer is negative. –25 –5 D. Signs are the same. = 5 Answer is positive.

Multiply or divide. A. 5(–2) Signs are different. = –10 Answer is negative. B. –3(–2) Signs are the same. = 6 Answer is positive.

Multiply or divide. –24 3 C. Signs are different. = –8 Answer is negative. –12 –2 D. Signs are the same. = 6 Answer is positive.

Order of Operations 1. Grouping symbols 2. Exponents 3. Multiply and divide from left to right. 4. Add and subtract from left to right. Remember!

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.

Simplify. C. –2(14 – 5) Subtract inside the parentheses. = –2(9) Think: The signs are different. = –18 The answer is negative.

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.

Simplify. C. –3(6 – 9) Subtract inside the parentheses. = –3(–3) Think: The signs are the same. = 9 The answer is positive.

The order of operations can be used to find ordered pair solutions of integer equations. Substitute an integer value for one variable to find the value of the other variable in the ordered pair.

A golfer plays 5 holes. On 3 holes, he has a gain of 4 strokes each A golfer plays 5 holes. On 3 holes, he has a gain of 4 strokes each. On 2 holes, he has a loss of 4 strokes each. Each gain in strokes can be represented by a positive integer, and each loss can be represented by a negative integer. Find the total net change in strokes. 3(4) + 2(–4) Add the losses to the gains. = 12 + (–8) Multiply. = 4 Add. The golfer changed by a total gain of 4 strokes.

A golfer plays 9 holes. On 3 holes, he has a gain of 3 strokes each A golfer plays 9 holes. On 3 holes, he has a gain of 3 strokes each. On 4 holes, he has a loss of 3 strokes each. Each gain in strokes can be represented by a positive integer, and each loss can be represented by a negative integer. Find the total net change in strokes. 3(3) + 4(–3) Add the losses to the gains. = 9 + (–12) Multiply. = -3 Add. The golfer changed by a total loss of 3 strokes.

1. –8(4) 2. 3. –2(13 – 4) 4. 6(-5 – 3) Homework Multiply or Divide. –12(5) –10 Simplify. 3. –2(13 – 4) 4. 6(-5 – 3) 5. Evin completes 11 transactions in his bank account. In 6 transactions, he withdraws $10. in 5 transaction, he deposits $20. Find the total net change in dollars.