Question

1又2分之1减6分之5加12分之7减20分之9加30分之11减42分之13加56分之15怎么简便计算?

Answer 1

1+ 1/2 - 5/6 + 7/12 - 9/20 + 11/30 - 13/42 + 15/56

= 1 + 1/2 - 3/6 - 2/6 + 4/12 + 3/12 - 5/20 - 4/20 + 6/30 + 5/30 - 7/42 - 6/42 + 8/56 + 7/56

= 1 + 1/2 - 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+ 1/8