1-3/5x(1/2-5/3)/7/4

问题描述:

1-3/5x(1/2-5/3)/7/4

1-3/5x(1/2-5/3)/7/4
=1-3/5x(-7/6)x4/7
=1+7/10x4/7
=1+2/5
=7/5