20: Yes, because 125-75=150. If you divide 150 by 6, you would get 25.
21: No, because 125-75=150. If you divide 150 by 4, you would get 37.5.
*22: 1
*23: 5
*Explanation for both 22 and 23: If the number was 15, then 15 divided 2 would be 7 remainder 1. If 15 was divided by 4, it would be 3 remainder 3.