(-1/4-31/80)+(7/24+9/40)

问题描述:

(-1/4-31/80)+(7/24+9/40)

(-1/4-31/80)+(7/24+9/40)
=(-20/80)+7/24+18/80
=7/24-33/80
=70/240-99/240
=-29/240