Maths strategy

This week the maths strategy I have learned is  using compensation to solve x problems.

Here is one example.

8 x 9 = 72                      7x8 = 56

(8 x 10) - (8 x 1)            (7 x 10 ) - ( 7 x 2 )

80 - 8 = 72                     70 - 14 = 56