To save time and master content, it is helpful for students to check the answer to one problem before doing 20. Thus, it would be great to have a check button option where students could put in an answer and check it to see if it's right before moving on to the next question. That way, they can continue working on that one question to get it right, before trying another. This saves them time, frustration, and helps each question be more productive. By doing this, the student should be able to do that last few problems on an assignment without needing multiple checks. If they can't, then they knew they need more help. I have used this type of homework for years in a moodle environment, I would love to see this come to Schoology.
As an example, I teach chemistry and students need to be able to correctly identify chemical formulas. So if they were asked for the formula of calcium carbonate, they should type in CaCO3. However, if they typed in CaC2, the computer would tell them they got it wrong and give them the chance to fix it and recheck. They could do this as many time as they wanted before moving on. This allows them to see that it was wrong, and learn the correct way to do it. So when they move on to the next question, they have that new understanding to help them address it. This really helps with calculation type questions.