# Project Euler - Problem 1
sum = 0
for i in xrange(1, 1001):
    if i % 3 == 0 or i % 5 == 0:
        sum = sum + i

print "The sum is: {}".format(sum)

# Project Euler - Problem 1
# 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.

def main(limit):
    sum = 0
    for i in xrange(1, limit):
        if i % 3 == 0 or i % 5 == 0:
            sum = sum + i

    print "The sum of all multiples of 3 and 5 below {} is: {}".format(limit, sum)

if __name__ == "__main__":
    main(10)
    main(1001)

Clean up problem 1 solution a bit.
Clean up problem 1 solution a bit.
