how do you add all the numbers between 50 and 100?

Question

the sum of all the numbers between 50 and 100?

Answer 1

We know the formula

Sum from 1 to n = n(n+1)/2

In this case we need  sum from 50 to 100.

First findout the sum 1 to 100

= 100(100+1)/2

= 5050

And now find the sum 1 to 50

= 50(50+1)/2

= 2550

Sum from 50 to 100  = 5050-2550

= 2500