1. Using Inverse Operations How to use an inverse to undo a repeated multiplication problem. 10 October, 2004

2. X 1.6 2.54 ÷1.6 2.5 So the inverse of X 1.6 is ÷1.6

3. X 1.6 2.54 X 0.625 2.5 Remember that the inverse X 1.6 is X 1/1.6 (1÷ 1.6 = 0.625)

4. X 1.6 2.54 X 1.2 4.8 1.6 X 1.2 = 1.92 So replace the two operations with this single operation 2.5 X 1.92 4.8

5. Find the single operation that replaces these two operations. Check your answers, in the same way as the previous example, using a starting number of 2.5 FirstSecondReplacement X 1.2X 2.5 X 1.4X 0.5 X 1.7X 2.3 X 1.6X 0.5 X 1.9X 1.5 X 1.7X 1.9 X 0.2X 0.4 X 0.5

6. X 1.6 2.54 X 1.2 4.8 First find 1.6 X 1.2 = 1.92 Find the reciprocal 1/1.92 = 0.5208333… Multiply by 0.5208333… This is the single inverse operation. 2.5 4.8 X 0.52083333…….

7. Find the single inverse operation that replaces these two operations. Check your answers, in the same way as the previous example, using a starting number of 2.5 FirstSecondSingle Inverse Operation X 1.2X 2.5 X 1.4X 0.5 X 1.7X 2.3 X 1.6X 0.5 X 1.9X 1.5 X 1.7X 1.9 X 0.2X 0.4 X 0.5