Question

tinh 1/1.2+1/2.3+1/3.4+.......+1/99.100

Answer 1

= 99/100

Answer 2

1/1.2+1/2.3+1/3.4+......+1/99.100

=1-1/2+1/2-1/3+1/3-1/4+..........+1/99-1/100

=1-1/100

=99/100

Answer 3

A=1-1/2+1/2-1/3+1/3-1/4+.....+1/99-1/100

A=1/100-1

A=99/100