What is the sum of all the natural numbers from 1 to 100 ?

Data series is :- 1 , 2, 3, 4,.....................,100

a = 1 , d = 1 and n = 100

Sum of Arithmetic progression is :-

S = \(\frac{n}{2}\)( 2a+ (n-1)d )

= \(\frac{100}{2}\)( 2 × 1 + (100-1)1 )

= 50 ( 2 × 1 + (100-1)1 ) 

= 50 ( 2 + 99)

= 5050

The correct answer is option (3) : 5050