Multiplying and Dividing Integers Sec 2.4 & 2.5

Multiplying Integers Let’s multiply! 8(3) = 24 What about when we have negative numbers? -4(-8) = Well, 4(8) = 32 as always, but what do we do about the sign? When multiplying The product of two integers with the same sign is positive, so… -4(-8) = 32

Multiplying Integers 9 * 20 = 180 -5 * -12 = 60 (-10)(-34) = 340 But what happens when the signs are different? The product of two integers with different signs is negative. (-5)(7) = -35

Multiplying Integers -8 * 11 = -88 -12 * 4 = -48 (-7)(9) = -63 (-6)(-7) = 42

Multiplying Integers Every month, the school loses 40 pencils. How many will it lose in a year? Write an expression for the above problem and solve it. There are 9 months in a school year, so 9 * 40 pencils = 360 pencils

Dividing Integers Division and multiplication are related. The rules for signs in integers work the same. The quotient of two integers with different signs is negative. Dividend ÷ Divisor = Quotient 12 ÷ -2 = -6 The quotient of two integers with the same signs is positive. (-65) ÷ (-5) = 13

Multiplying and Dividing Integers (-9) ÷ 3 = -3 (-11)(-12) 132 200 ÷ - 20 = -10 7 * (-3) = -21 (-81) ÷ (-3) = 27