In our last unit we worked on adding two digit numbers in our heads. This next unit, we will work on subtracting double digit numbers in our head. Below you will find some examples of strategies we will use to help us solve these problems mentally.
Subtracting tens and ones:
55-20= 35
55 45 35
10 10
64-23= 41
64 54 44 43 42 41
10 10 1 1 1
Adding on to find the missing part:
55-20= 35
20+__=55
20 30 40 50 55
10 10 10 5 = 35
64-23= 41
23+__= 64
23 33 43 53 63 64
10 10 10 10 1= 41
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