Question

find the sum of the first 80 numbers

Answer 1

sum of n natural numbers = n(n+ 1 )/ 2
sum of 80 natural numbers = 80× 81 /2
= 40 × 81 = 3240

Answer 2

Dear user !!

Sum of n numbers ( consecutively starting ) is given by : n ( n+1 )/2

Here, n = 80

===> Sum = (80 X 81)/2

                  = 40 X 81

                   = 3240 >>>>Ans.

Hope it helps you !!