计算1/6+1/12+1/20+1/30+1/42+2/56

计算1/6+1/12+1/20+1/30+1/42+2/56
计算1/6+1/12+1/20+1/30+1/42+2/56

计算1/6+1/12+1/20+1/30+1/42+2/56
1/6+1/12+1/20+1/30+1/42+1/56
=(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
如果是
1/6+1/12+1/20+1/30+1/42+2/56
=3/8+1/56
=22/56
=11/28

不知道

1/6+1/12+1/20+1/30+1/42+2/56
=3/8+1/56
=22/56
=11/28

原题可变形为(1/(2*3)+1/(3*4)+1/(4*5)+……+1/(7*8))+1/56
上式的前半部分，有规律得：
=(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+(1/5-1/6)+(1/6-1/7)+(1/7-1/8)=3/8
所以原式=3/8+1/56=11/28