Question

二分之一加六分之一加十二分之一加二十分之一加三十分之一加四十二分之一加五十六分之一加七十二分之一？

Answer 1

列式计算如下图所示:

Answer 2

1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72
=(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)+(1/8-1/9)
=1-1/9
=8/9

Answer 3

原式=1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72
=（6+2+1）/12+1/20+1/30+1/42+1/56+1/72
=3/4+1/42+1/56+1/72+5/60
=（42+1）/56+1/42+1/72+1/12
=43/56+1/42+（1+6）/72
=（43x6+8）/336+7/72
=266/336+7/72
=（266x6+7x28）/2016
=（1596+196）/2016
=1792/2016
=56/63
≈0.889