Question

Without adding the numbers, find the sum of successive odd numbers 1, 3, 5, 7, 9, 11, 13 and 15.

Answer 1

We know that the sum of first n odd natural numbers is $n^2$
Given odd numbers are 1, 3, 5, 7, 9, 11, 13 and 15.
So, number of odd numbers, n = 8
$\therefore$ The sum of given odd numbers $=n^2=(8{)}^2=64$