Answer
See explanation below.
Work Step by Step
1. Assume n is a positive integer that equals the sum of the positive integers not exceeding it.
n = n + (n-1) + (n-2) + (n-3) + ... + 2 + 1
2. Summation formula
n = n(n+1)/2
3. Simplify
2n = n^2 + n
0 = n^2 - n
0 = n(n - 1)
Therefore, n = 0 or n = 1
The only positive integer that equals the sum of the integers not exceeding it is n = 1