Subtraction Strategies
Use what works for you!!!
Use a known fact
15 - 7 = 8 so 150 - 70 = 80
Count back
110 - 22 is the same as 110 - 10 - 10 - 2
Use doubles
Double 150 = 300 so 300 - 150 = 150
Count on
134 - 128 = 6 because 128 + 6 = 134
Subtract the parts
146 - 23 is the same as 146 - 20 - 3
Use place value
248 - 123 is the same as (200 - 100) + (40 - 20) + (8 - 3) or (8 - 3) + (40 - 20) + (200 - 100)
Round or adjust
38 - 19 is the same as 38 - 20 + 1
15 - 7 = 8 so 150 - 70 = 80
Count back
110 - 22 is the same as 110 - 10 - 10 - 2
Use doubles
Double 150 = 300 so 300 - 150 = 150
Count on
134 - 128 = 6 because 128 + 6 = 134
Subtract the parts
146 - 23 is the same as 146 - 20 - 3
Use place value
248 - 123 is the same as (200 - 100) + (40 - 20) + (8 - 3) or (8 - 3) + (40 - 20) + (200 - 100)
Round or adjust
38 - 19 is the same as 38 - 20 + 1