Addition, subtraction, multiplication and division are collectively referred to as elementary arithmetic, in which addition and subtraction are called first-level operations; Multiplication and division are called secondary operations.

operation sequence

1, same level, from left to right; 2. Two-stage operation, first multiply and then divide, then add and subtract.

3. When there are brackets, count the inside of brackets first, and then count the outside of brackets;

4. When there are multiple brackets, count the brackets first, then the brackets inside, then the braces inside, and finally the brackets outside.

5. If there is a power, calculate the power first.

6. In the mixed operation, the numbers in parentheses are calculated first, and the parentheses are from small to large. If there is a power, calculate the power first, and then from high to low.