linkProblem 1 - Multiples of 3 and 5

linkQuestion

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.

linkSolution

euler_001.py
1linktotal = 0

2linkfor num in range(1, 1000):

3link    if num % 3 == 0 or num % 5 == 0:

4link        total += num

5link

6linkprint(total)

7link

8link# --> Alternate answer that uses list comprehension

9linkprint(sum([num for num in range(1, 1000) if (num % 3 == 0 or num % 5 == 0)])) # // @see [List Comprehension](https://www.programiz.com/python-programming/list-comprehension)

linkDiscussion

• We use the range function to generate numbers 1 to 999 since the problem wants us to find the sum of all multiples of 3 or 5 below 1000.
• To check if a number is a multiple of 3 or 5, we will use the modulo operator. The modulo operator retrieves the remainder after a division. A number is a multiple of another number if their remainder is 0.
• This is short hand for total = total + num

linkAnswer