Question

1/1-1/2+1/2-1/3+1/3-...-1/2020+1/2020-1/2021

Answer 1

1/1-1/2+1/2-1/3+1/3-...-1/2020+1/2020-1/2021

=1/1+(1/2-1/2)+(1/3-1/3)+...+(1/2020-1/2020)-1/2021

=1/1-1/2021

=1-1/2021

=2020/2021

Học tốt nha!!!