@Aliya562219 10. The difference between 8 to 7 is 18, the difference between 7 to 6 is 16, the difference between 6 to 5 is 14. So the difference between 5 to 3 is 10. It would be 12 if the question was 4 but, the question is 3 so the answer is 10.
@arabelladevine I've been doing this lately because it's cold outside. I would also walk up and down the stairs, do side jumps one leg at a time, and run in place.