Question

五分之四减四分之五减五分之一等于多少?

Answer 1

4/5-5/4-1/5
=16/20-25/20-4/20
=-13/20
或：
4/5-5/4-1/5
=(4/5-1/5)-5/4
=3/5-5/4
=12/20-25/20
=-13/20