# Sum Of Multiples Given a number, find the sum of all the unique multiples of particular numbers up to but not including that number. If we list all the natural numbers below 20 that are multiples of 3 or 5, we get 3, 5, 6, 9, 10, 12, 15, and 18. The sum of these multiples is 78. ## Source A variation on Problem 1 at Project Euler [http://projecteuler.net/problem=1](http://projecteuler.net/problem=1) ## Submitting Incomplete Solutions It's possible to submit an incomplete solution so you can see how others have completed the exercise.