Multiply first, then divide, then add and subtract. If there are parentheses, calculate the value in parentheses first.

Step by step calculation is to calculate step by step according to the algorithm. The step-by-step calculation steps are as follows:

Step 1: Calculate the contents in brackets. If there are no brackets, skip this step.

Step 2: Calculate the multiplication and division method.

Step 3: Calculate the addition and subtraction to get the final operation result.