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Learn the rules for multiplying and dividing integers, including how to determine the sign of the answer based on the signs of the numbers. Includes examples and practice problems.
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Rules for Multiplying Integers Multiply the numbers Same signs, answer is positive. Different signs, answer is negative.
Rules for Dividing Integers Divide the numbers Same signs, answer is positive. Different signs, answer is negative.
Examples with Multiplication 20 (Same signs, answer is positive) -20 (Different signs, answer is negative) 20 (Same signs, answer is positive) -20 (Different signs, answer is negative) 5 × 4 = 5 × -4 = -5 × -4 = -5 × 4 =
Examples with Division 7 (Same signs, answer is positive) -7 (Different signs, answer is negative) 7 (Same signs, answer is positive) -7 (Different signs, answer is negative) 21 ÷ 3 = 21 ÷ -3 = -21 ÷ -3 = -21 ÷ 3 =
Practice Problems -42 10 -36 6 -5 -66 -8 56 -10 30 1. -50 ÷ -5 = 6. 7 × -6 = 2. -9 × 4 = 7. -48 ÷ -8 = 3. 60 ÷ -12 = 8. -11 × 6 = 4. -8 × -7 = 9. 72 ÷ -9 = 5. -100 ÷ 10 = 10. -15 × -2 =
Word Problems • The temperature is currently at 10°Fahrenheit. The temperature decreases 7 degrees every hour. If 2 hours pass, what is the new temperature? • 7 × 2 = 14 so it decreases 14 degrees 10 – 14 = -4°F • Jane has $125 in her bank account. Her cell phone bill is $47 a month. If she pays that bill two months in a row and doesn’t buy anything else or deposit any money, how much money does she have left? • 47 × 2 = $94 to pay the bills $125 - $94 = $31 left