Question

Find the sum of 1-2+3-4+5-6......100 in a easy method


Please help me to solve this problem

Answer 1

use calculator.....
its very easy...
or
search on internet...

Answer 2

According to the statements the question is that addition of odd no.s - addition of even no.s.

Addition of consecutive odd no.s=

Eg. 1+3=2^2

1+3+5=3^2

It basically means the square of the total no.s present.

There are 50 odd no.s between 1 to 100=50^2=2500

Addition of consecutive even no.s=

=n×(n+1)

=50×51

=2550

Addition of the total no.s =2500-2550

=-50