(Not answering the question you asked, but hopefully a useful answer nonetheless) My son discovered he'd been faking math and not retaining and understanding i

(Not answering the question you asked, but hopefully a useful answer nonetheless) My son discovered he'd been faking math and not retaining and understanding it. He had excellent success using https://brilliant.org/ https://brilliant.org/ to restart at early high school math and work forward, learning it properly. Just got an A for his second year university maths class on the strength of it.