The puzzle that we solved this week can be solved by hand, but excel is a very useful tool!
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.
This puzzle was taken from Project Euler Website, where there are lots more puzzles to try, all designed to be solved with a computer.