Question

3分之4-12分之7+20分之9-30分之11+42分之13-56分之15简便运算

Answer 1

4/3-7/12+9/20-11/30+13/42-15/56

=4/3-(1/3+1/4)+1/4+1/5-(1/5+1/6)+1/6+1/7-(1/7+1/8)

=1-1/8

=7/8