# Finding the sum of all the multiples of 3 or 5 below 1000

This problem comes from Project Euler. Project Euler is a website with a bunch of computational problems designed to be solved with software applications.

**find_sum_of_multiples.rb**

```
=begin
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.
=end
class Euler
def self.sum_of_multiples(number)
range = (1...number).to_a
sum = 0
range.each do |n|
if n % 3 == 0 || n % 5 == 0
sum += n
end
end
puts sum
end
end
```

This can be executed from the command line by running:

*ruby -r "./find_sum_of_multiples.rb" -e "Euler.sum_of_multiples 1000"*