# 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.

## Hints
This exercise requires you to process a collection of data. You can simplify your code by using LINQ (Language Integrated Query).
For more information, see [this page](https://docs.microsoft.com/en-us/dotnet/articles/standard/using-linq).


## 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.