Answer
5050
Work Step by Step
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + . . . . .+ 100
First term $a_{1}$ = 1
Common difference d = 1
Sum of n terms = $\frac{n}{2}$($a_{1}$ + $a_{n}$)
Sum of first 100 natural numbers = $\frac{100}{2}$(1 + 100)
= 50$\times$101 = 5050
