1. Fast Sum: When the sum of a series needs to be calculated, the method of fast sum can be used to simplify the calculation. For example, for the sum 1+2+3+...+n, the result can be quickly calculated by [(n+ 1) x n]/ 2.

2. prime factor decomposition: prime factor decomposition is a common method to find the greatest common divisor and the least common multiple. A number can be decomposed into smaller prime factors, thus simplifying the operation. For example, for 30, it can be decomposed into 2x3x5.

3. Multiplication method: Multiplication method refers to solving some problems by repeated multiplication, such as finding the square root of a certain number, which can be approximated by repeated multiplication, thus greatly reducing the amount of calculation.

4. similar triangles Theorem: similar triangles Theorem is a commonly used method in triangle similarity. For example, if the sides of two triangles are equal, the two triangles are similar and their corresponding angles are the same.

The above are some simple math problem calculation methods. If faster and more accurate calculation results are needed, different methods can be used comprehensively according to specific problems.