IIFE | Sum all numbers up to a limit

// IIFE to sum all numbers up to a limit.
// https://en.wikipedia.org/wiki/1_%2B_2_%2B_3_%2B_4_%2B_%E2%8B%AF
// In this case, the limit is 100:
(function(N){ return ( N * ( N+1 )) / 2;})(100);