1, there are two kinds of multiple-choice questions in the math part of GMAT-PS (problem solving) and DS (data adequacy judgment). If your junior high school math is not bad, you don't need to spend too much time on the math part, just recite the core math vocabulary.

2. General GMAT mathematics is not very difficult, calculus is rarely involved, and it is at the middle and high school level on average, so don't worry too much. Part of mathematics knowledge from elementary school to high school, including four operations of numbers, parity, divisibility, remainder characteristics, sets, permutation and combination probability, algebra, solving equations, solving inequalities, simple application problems, simple geometry and so on.

I wish you a happy study.