Algebra2go® Division with Negative Numbers Objective 1 Perform Division with Negative Numbers Remember that multiplication represents repetitive addition of a number. Recall 4 ⋅ 3 = 4 + 4 + 4 = 12 This means that “4 goes into 12” three times! 4 4 4 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 We can see that it takes three 4’s to make 12. 3. 12 , this means 12 ÷ 4 = Since 4 ⋅ 3 = 12 12 Note: 4 = 3 since 4 ⋅ 3 = Do you see a pattern in the above note? ( −4) + ( −4) + ( −4) =−12 Recall: −4 ⋅ 3 = We can see that it takes three -4’s to make -12. 3. − 12 , this means − 12 ÷(− 4) = Since − 4 ⋅ 3 = Note: −−12 4 = 3 since − 4 ⋅ 3 =− 12 Do you see a pattern in the above note? Notice that negative divided by negative is positive! Page 1 of 4 Algebra2go® Understanding our multiplication tables can help us with mentally determining basic division problems. Notice that since 7 ⋅ 3 = 3 ⋅ 7 =21 we can conclude that 21 3= 21 7 = d an . 3 7 Similarly, since -7 ⋅ 3= 7 ⋅(-3)= -21 we can conclude that -21 -3 -21 -7 an = = d . 3 7 We can now make a general conclusion regarding division with integers. When dividing two numbers with the same sign, the quotient will be positive. When dividing two numbers with different signs, the quotient will be negative. Page 2 of 4 Algebra2go® Example 1: Find each quotient and then rewrite it as an equivalent multiplication problem by filling in the blank. 15 = a) 5 -42 = b) 7 45 = c) -9 -54 = d) -6 since 7 ⋅( ___) -42 = since -9 ⋅ ___ 45 = = since -6 ⋅ ___ -54 0 = e) -12 = since -12 ⋅ ___ 0 -84 = f) 4 = since 4 ⋅( ___) -84 -128 = g) 8 since 8 ⋅( ___) -128 = 162 = h) -9 = since -9 ⋅ ___ 162 216 = i) -12 Page 3 of 4 since 5 ⋅ ____ 15 = = since -12 ⋅ ___ 216 Algebra2go® Answer the following homework questions. In Exercises 1 – 6, find each quotient. ÷ (-7) 132 ÷ (-11) ÷ (-8) -54 ÷ 9 ÷ (-4) ÷ 5 -56 ÷ (-7) ÷ 8 1) 28 3) -32 5) 40 2) 4) 6) In Exercises 7 – 10, write each word statement as a mathematical expression then find the value of the expression. 7) The quotient of -30 and 5. 8) Subtract -3 from the quotient of 27 and -9. 9) The quotient of -3 squared and -9. 10) The product of -1 and -4 squared, divided by -2. In Exercises 11 – 19, evaluate each expression. 20 4(-6) 11) -4 14) -3 17) (-2)2 + 20 ÷ 4 0 7(-6) 2 12) -8 15) -3(-2) 18) -3 + 24 ÷( −8) -6 2 2 2 13) 0 16) (-3) + 21 ÷ 7 19) -2 −(-8) ÷(-4) Page 4 of 4