3分之2减12分之7加20分之9减30分之11加42分之13减56分之15
=(1/2+1/3)-(1/3+1/4)+(1/4+1/5)-(1/5+1/6)+(1/6+1/7)-(1/7+1/8)
=1/2-1/8
=3/8
依何格格,你好:
2/3-7/12+9/20-11/30+13/42-15/56
=2/3-1/3-1/4+1/4+1/5-1/5-1/6+1/6+1/7-1/7-1/8
=1/3-1/8
=5/24
3分之2减12分之7加20分之9减30分之11加42分之13减56分之15
=2/3-(1/3+1/4)+(1/4+1/5)-(1/5+1/6)+(1/6+1/7)-(1/7+1/8)
=2/3-1/3-1/4+1/4+1/5-1/5-1/6+1/6+1/7-1/7-1/8
=1/3-1/8
=5/24
3分之2减12分之7加20分之9减30分之11加42分之13减56分之15
=2/3-7/12+9/20-11/30+13/42-15/56
=8/12-7/12+27/60-22/60+52/168-45/168
=1/12+1/12+1/24
=5/24
24分之5