1. Reverse Subtraction Objectives:  do a subtract by adding  check your answer by adding

2. Objective: do a subtract by adding Look at this addition:20 + 14 = 34 Now look at these two subtractions: 34 – 14 = 20 and 34 – 20 = 14

3. Objective: do a subtract by adding Another example:34 + 27 = 61 Now look at these two subtractions: 61 – 34 = 27 and 61 – 27 = 34

4. 20 - 7 Rewrite the sum 7 + 1 0 + 2 0 3 1 0 =13 Check the answer Does 13 + 7 = 20? 13 +7 20

5. 50 - 26 Rewrite the sum 2 6 + 3 0 + 5 0 4 2 0 =24 Check the answer Does 26 + 24 = 50? 26 +24 50

6. 100 - 28 Rewrite the sum 2 8 + 3 0 + 1 0 0 2 7 0 =72 Check the answer Does 28 + 72 = 100? 28 +72 100

7. 43 - 25 Rewrite the sum 2 5 + 3 0 + 4 3 5 1 3 =18 Check the answer Does 25 + 18 = 43? 25 +18 43

8. 92 - 34 Rewrite the sum 3 4 + 4 0 + 9 2 6 5 2 =58 Check the answer Does 34 + 58 = 92? 34 +58 92

9. I can do subtractions  By doing an add  I can also check any subtraction by adding