Add all the natural numbers below one thousand that are multiples of 3 or 5.

Seems simple enough? Here’s my brute force way of answering it (using Python):

#initiate the counters
n = 1
sumTo = 0
#iterate up to 1000, adding natural numbers that are multiples of 3 or 5
while n < 1000:
if (n%3 == 0) or (n%5 == 0):
sumTo = sumTo + n
n = n + 1
else:
n = n + 1
print (sumTo)

There’s probably a more elegant way of solving this, but hey, it’s a start! How would you solve it?