If you are confused and can't work out the result, but the time for doing the problem has increased, it should be that the foundation itself is not very good. It is the best way to brush multiple-choice questions and practice your hands all the time. If the question is miscalculated because of impatience, the method is as above.
Nothing is more effective than sinking down and brushing the questions. For real test papers and simulation questions, brush multiple-choice questions and brush feelings. As an experienced person, I hope I can help you.