125/7=17又7分之6
简算
1.2-0.5*1.8/0.9
=1.2-0.9/0.9
=1.2-1
=0.2
8*7*1.25
=8*1.25*7
=10*7
=70
3分之2+（6分之5-4分之3）/8分之3
=2/3+1/12×8/3
=2/3+2/9
=8/9
7分之5/9+7分之4*9分之1
=（5/7+4/7）*1/9
=1*1/9
=1/9