=1/5-1/4
=4/20-5/20
=(4-5)/20
=-1/20再問你幾個問題（8分之3減4分之1）除以8分之36分之5乘4減（8分之7加3分之2）5減8分之七減0.125 全部都是用簡便運(yùn)算
(3/8-1/4)/3/8
=3/8*38-1/4*3/8
=1-2/3
=1/3
5/6*4-(7/8+2/3)
=10/3-(21/24+16/24)
=80/24-35/24
=45/24
=15/8
5-7/8-0.125
=5*8-7/8*8-0.125*8
=40-7-1
32