Multiply and Divide Integers 2.3 Multiply and Divide Integers

Review -12+8 0-(-9) -7+(-4) 2-(-4) -6-(-9)-(4)+13 Write the sum of y and negative five True, sometimes true or false: The difference between a number and its additive inverse is zero The sum of a negative number and a negative number is a negative number

Multiplying Steps for Multiplying Integers 1. Multiply the numbers and ignore their signs 2. If both have the same signs (positive-positive or negative-negative) then the answer is a positive number. 3. If they opposite signs (one negative and one positive) then the answer is negative.

Examples -7(4) = -28 3(-2) = -6 4(5) = 20 (-6)(-1) = 6

Properties Multiplicative property of zero A*0 = 0 Multiplicative property of one a*1 = a Commutative property a*b = b*a 2*3 = 3*2 Associative Property of Multiplication (a*b)*c = a*(b*c)

Division Same rules as multiplication 1. Divide the numbers and ignore their signs 2. If both have the same signs (positive-positive or negative-negative) then the answer is a positive number. 3. If they opposite signs (one negative and one positive) then the answer is negative.

Properties Top = numerator Bottom = denominator a / 1 = a 0 / a = 0 Zero cannot be in the denominator a/0 = undefined b/a is okay as long as a does not equal 0

examples -2 / -2 = 1 50 / -10 = 5

Try it (-38)(51) -1938 -7(-8)(9)(-2) -1008 Is -3 a solution to 12 = -4a Yes’m What is zero divided by -17 Zero 84/-6 -14 Is -3 a solution to: -6/y = -2 No! The daily high temperatures for one week in winter were: -7, -8, 0, -1, -6, -11, -2 -5

2.3 homework 1 thru 119 EOO 20, 36, 48, 60, 80, 84, 90, 100, 108, 112