1/4+1/28+1/70.+1/9700
问题描述：
1/4+1/28+1/70.+1/9700
答
原式=1|4+1|4*7+1|7*10+......1|97*100（共有（100-1）|3=33个数）
=33|（33*3+1）=33|100
答
1/4+1/28+1/70......+1/9700
=(1/3)*(1-1/4+1/4-1/7+1/7-1/10+...+1/97-1/100)
=(1/3)*99/100
=33/100
答
=1/1*4+1/4*7+1/7*10+……+1/97*100=(1/3)*(1-1/4)+(1/3)*(1/4-1/7)+(1/3)*(1/7-1/10)+……+(1/3)*(1/97-1/100)=(1/3)*(1-1/4+1/4-1/7+1/7-1/10+……+1/97-1/100)=(1/3)*(1-1/100)=33/100