Project Euler – Problem 1

If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23.

Find the sum of all the multiples of 3 or 5 below 1000.

Scala:

(1 to 999).filter(x => (x % 3 == 0 || x % 5 == 0)).
    foldLeft(0)((b, a) => b + a)