Answer:
33
Explanation:
So all the single-digit positive whole numbers that evenly divide 72 would be:
1 (72 / 1 = 72)
2 (72 / 2 = 36)
3 (72 / 3 = 24)
4 (72 / 4 = 18)
6 (72 / 6 = 12)
8 (72 / 8 = 9)
9 (72 / 9 = 8)
Then, 1 + 2 + 3 + 4 + 6 + 8 + 9 = 3 + 7 + 14 + 9 = 10 + 23 = 33