# Sum all the multiples of 3 or 5 below 1000

fn mod(n: Number, d: Number): Number
    while n >= d
   	    n = n - d
    end
	n
end

fn is_multiple(n: Number, d: Number): Bool
    mod(n, d) == 0
end

fn sum_to(n: Number): Number
   var i = 0
   var s = 0
   while i < n
     s = ((s + i) if is_multiple(i, 3) else
	 	  ((s + i) if is_multiple(i, 5) else s))
     i = i + 1
   end
   s
end

print is_multiple(3, 3) #=> true
print is_multiple(9, 3) #=> true
print is_multiple(8, 3) #=> false

print sum_to(10) #=> 23
print sum_to(1000) # => 233168