Question

shot cut for 1+2+3+4+..........+100

Answer 1

use the formula n(n+1)/2
here, 100(100+1)/2=1+2+3+......+100
=50×101=5050

Answer 2

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

Sum from 1 to 100 =100(100+1)/2
=50×101
= 5050