(5/3*7)+(5/7*11)+(5/11*15)+.+(5/55*59)的计算过程

5/3*7=(5/3-5/7)*4;
5/7*11=(5/7-5/11)*4;
所以(5/3*7)+(5/7*11)+(5/11*15)+......+(5/55*59)=
20*(1/3-1/7+1/7-1/11+1/11-......-1/59)=
20*(1/3-1/59)=
70/177

(5/3*7)+(5/7*11)+......+(5/55*59)
=5*[(1/3*7)+(1/7*11)+......+(1/55*59)]
=5/4*(1/3-1/7+1/7-1/11+......+1/55-1/59)
=5/4*(1/3-1/59)
=70/177
我也想知道为什么我老慢~~悲哀ing

=(5/4)*(1/3-1/7)+(5/4)*(1/7-1/11)+(5/4)*(1/11-1/15)+……+(5/4)*(1/55-1/59)
=(5/4)*(1/3-1/59)
=70/177

(5/3*7)+(5/7*11)+(5/11*15)+......+(5/55*59)
=5/4*(1/3-1/7+1/7-1/11+...+1/55-1/59)
=5/4*(1/3-1/59)
=70/177
他舅为什么你总是比我快？