Integers Multiplication and Division - Math

Integers Multiplication and Division Objective : to be able to multiply and divide negative numbers. The Rules: Multiplying Dividing +ve x +ve = +ve +ve ÷ +ve = +ve -ve x -ve = +ve -ve ÷ -ve = +...

Integers Multiplication and Division Objective : to be able to multiply and divide negative numbers. The Rules: Multiplying Dividing +ve x +ve = +ve +ve ÷ +ve = +ve -ve x -ve = +ve -ve ÷ -ve = +ve +ve x -ve = -ve +ve ÷ -ve = -ve -ve x +ve = -ve -ve ÷ +ve = -ve If the signs are the SAME the answer is POSITIVE If the signs are DIFFERENT the answer is NEGATIVE Example 1 -12 x -4 -ve x -ve = +ve The signs are the same so the answer is POSITIVE! Just do as you would normally do when multiplying the numbers. = 48 Try: 1) -7 x -2 2) -9 x -10 3) -11 x -19 4) -2 x -5y Example 2 63 ÷ -7 Do the calculation as if it was just 63 ÷ 7. (= 9) Decide which rule you need to use. +ve ÷ -ve = -ve (The signs are different so the answer is NEGATIVE) = -9 Questions Answers 1) 3 x – 4 1) -12 2) -7 x -2 2) 14 3) 9 x 9 3) 81 4) 6 x -6 4) -36 5) 4 x -1 x 3 5) -12 6) -20 ÷ 5 6) -4 7) -100 ÷ -10 7) 10 8) -10 x 2 8) -20 9) -11 x -19 9) 209 10) - 450 ÷ - 5 10) 90 11) 36 ÷ -6 11) -6 12) -7 x 11 12) -77 13) -12 x 11 13) -132 14) -3 x -20 14) 60 15) -6 x -3 ÷ 2 15) 9 Can you do these?? 1892 ÷ (-3) (-9)² Negative numbers and Algebra: Sometimes you need to remember these rules in order to simplify algebra. Example: a) -2 ( 5x – 4) b) 9 ( 2y – 7)