Question

1/2+1/6+1/12+1/20+1/30+1/42

Answer 1

1/2 + 1/6 + 1/12 + 1/20 + 1/30 + 1/42

= 2/3 + 1/12 + 1/20 + 1/30 + 1/42

= 3/4 + 1/20 + 1/30 + 1/42

= 4/5 + 1/30 + 1/42

= 5/6 + 1/42

= 6/7

đ/s : ...

Answer 2

1/2+1/6+1/12+1/20+1/30+1/42 

=1/2-1/42

=10/21