Question

Find the sum of the first 378 counting numbers


WITH SOLUTION

Answer 1

Explanation:

Counting numbers are 1,2,3,4,5........,378

Here it forms an AP with a = 1, d=1, an or l=378, n=378

Sum of 378 numbers = n/2(a+l)

= 378/2(1+378)

= 189(379)

= 71631