能简算的要简算.1/5÷6/25-2/7×7/8

问题描述:

能简算的要简算.1/5÷6/25-2/7×7/8

1/5÷6/25-2/7×7/8
=1/5×25/6-1/4
=5/6-1/4
=10/12-3/12
=7/12