Looking at number 4, you first have to look at the information that you have: On tuesday he practiced for 1 5/6 hrs Monday he practiced for 7/10 hrs He is supposed to practice for 1 1/4 hr. You could write questions like: How much more did Marco practice on Tuesday than he is supposed to practice? This works because it does indeed involve subtraction, you would be subtracting the amount that he should have practiced from the amount of time that he did practice. If I didn't answer the question, please message me and I will clarify!