Subtraction Strategies

Today we revised how to add and subtract. Here are two strategies showing how to solve a subtraction problem.

The question: 57 - 29 = 

Strategy 1: 

57 - 29 = ?
29 + _ = 57

29 + 20 = 49

49 + 8 = 57 

20 + 8 = 28

Strategy 2:
57 - 29 =
57 - 20 = 37
37 - 9 = 28

So the answer to 57 - 29 = 28.