Question

4/2+4/6+4/12+4/20+...+4/90

Answer 1

Ответ:

4/2+4/6+4/12+4/20+4/30+4/42+4/56+4/72+4/90=

2+2/3+1/3+1/5+2/15+2/21+1/14+1/18+2/45=2+1+1/3+

+1/6+1/5=3+7/10=3,7