Question

Find the sum of all the even integers from 12 to 1980

Answer 1

1961124

Explanation:

The sum of consecutive positive integers from n1 to n2 is equal to:

n₁ + (n₁ + 1) + ... + n₂ = n₂(n₂ + 1) / 2 - n₁(n₁ - 1) / 2