8分之7—(4分之3—4分之3乘6分之5)
=7/8-(3/4*(1-5/6))
=7/8-(3/4*(1/6))
=7/8-1/8
=3/4
(9分之8减3分之橘岁1)除以(2分之1乘3分之2)
=(8/9-1/3) /(1/2*2/3)
=(8/9-1/3) /(1/3)
=(8/9-1/圆或睁3) *3
=8/3-1
=5/3
13乘5分之4加3除以4分团陪之5 减5分之4
=13*4/5+3/(5/4)-4/5
=13*4/5+3*4/5-4/5
=(13+3-1)*4/5
=15*4/5
=12