12.5×0.25×3.2=12.5×0.25×(8×0.4)=(12.5×8)×(0.25×0.4)=100×0.1=10
12.5x0.25x3.2=12.5x0.25x0.8x4=(12.5x0.8)x(0.25x4)=10x1=1
0.67*99=0.67*(100-1)=0.67*100-0.67=67-0.67=66.33
