Is it better to memorize mark schemes or understand the question and do it again

Im thinking about memorising mark schemes as most of the tests in my school are questions from the topic tests on pmt.Should I?

It depends on your objective. If you goal is do well in school tests (without having to actually understand the subject), then memorising mark schemes is a reasonable approach.

If, however, you want to ultimately do well in external exams then it'd be far better to actually understand the question (and the answer, obviously).

Im thinking about memorising mark schemes as most of the tests in my school are questions from the topic tests on pmt.Should I?

No, you need to understand the ideas. Topics tests are straightforward compared to exam questions.