Think about solving problems:

When there is only one level of operation, it is calculated from left to right;

When there are two levels of operation, multiply first and then divide, then add and subtract.

When there are brackets, count them first;

When there are multiple parentheses, count the parentheses first.

If there is a square, count it first.

In the mixed operation, the numbers in parentheses are calculated first, and the parentheses are from small to large. Then from high to low.