二分之一加六分之五加十二分之十一加二十分之十九加三十分之二十九
=6-(1/2+1/6+1/12+1/20+1/30)
=6-(1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6)
=6-(1-1/6)
=5又1/6
原因
1/2=1-1/2
5/6=1-1/6
11/12=1-1/12
19/20=1-1/20
29/30=1-1/30
这6个数每个看作1,
所以是6-(1/2+1/6+1/12+1/20+1/30)
二分之一+六分之五+十二分之十一+二十分之十九+三十分之二十九
=(1-1/2)+(1-1/6)+(1-1/12)+(1-1/20)+(1-1/30)
=5-(1/2+1/6+1/12+1/20+1/30)
=5-(1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6)
=5-(1-1/6)
=5-5/6
=4又1/6
原式=(1-1/2)+(1-1/6)+(1-1/12)+(1-1/20)+(1-1/30)=5-(1/2+1/6+1/12+1/20+1/30)=25/6