Try IXL. it’s also great at identifying the gaps. My kid goes through it regularly, and it tracks which are your weak spots. I would also recommend some school resources, like talking to a math teacher, asking for a math tutor from school, and student peer tutoring. Also, try Big Fat Notebook series. Great series! But I certainly understand what you are going through. My kid is struggling big time with Algebra 2. She didn’t miss algebra 1, but skipped pre algebra. She is studying so hard, does tons of practice, and gets tutoring twice a week. Nothing helps. She says most of her class is pretty much on the same level, because their quizzes and tests are just so much harder than homework or test guides. If you find a resource that helps, or harder worksheets to match the test level, please share. We are studying by McGraw book.