C# mod operator

There are four whole numbers below the number 14 that are multiples of either 4 or 7.
They are: 4, 7, 8 and 12
The sum of these numbers is 31
Write a C# program to find all the multiples of either 4 or 7 between, and including, 100 and 120.
Sum the found multiples and print the total out to the console.

For bonus points, also print out how long your program took to execute.
Please help im a coldfusion developer and not exactly sure about this...