I learned four algorithms in primary school, and the formula is:

Clear order is the key to the calculation of mixed test questions.

The operation at the same level is the best, and it is calculated from left to right in turn.

There are two levels of operations, first multiplication and division, then addition and subtraction.

What should I do if I encounter parentheses? Parentheses take precedence.

Check every step, and be happy when you are right.

1. In the formula without brackets, if there is only addition, subtraction, multiplication and division, it is calculated from left to right.

2. If there is any addition, subtraction, multiplication and division of brackets, multiply first, then divide and then add and subtract.

3. Parentheses are counted in brackets first, and outside brackets.