Question

помогите пожалуйста 120+130+142+156+172+190

Answer 1

1/20+1/30+1/42+1/56+1/72+1/90=3/20

1/20+1/30=5/60=1/12

1/12+1/42=9/84=3/28

3/28+1/56 =14/112=1/8

1/8+1/72=10/72=5/36

5/36+1/90=27/180=3/20