compensating

W.A.L.T- us compensating to work out problems.

6 x 10 = 60

so

6 x 9 =  54  1 x 6 = 6

4 x 20 = 80

so

4 x 18 = 72  2 x 4 =8

Dubble and half

W.A.L.T-use the double and half strategy

5 x 18 = 90

you change the 5 into a 10
                                          so
then you half the 18 into 9

10 x 9 = 90