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