Not just math.
Start with the simplest test paper. It doesn't matter at first. Look at the answer steps first, analyze how each step is obtained, then change a similar question, do it yourself, compare the answers and see how much you can get. Focus on analyzing your own wrong steps. Accumulate a little and increase the difficulty. Remember, to improve mathematics, we must ensure the amount of questions, so that we will not be confused when we see different questions.