(1/2-1/3)+(1/4-1/5)+(1/7-1/10)+(1/14-1/15)+(1/28-1/30)

问题描述:

(1/2-1/3)+(1/4-1/5)+(1/7-1/10)+(1/14-1/15)+(1/28-1/30)
要求简便运算.

(1/2-1/3)+(1/4-1/5)+(1/7-1/10)+(1/14-1/15)+(1/28-1/30)
=(1/2+1/4)+(1/7+1/14+1/28)-(1/3+1/5+1/10+1/15+1/30)
=3/4+1/4-11/15
=4/15