The use of parentheses and parentheses in primary school mathematics should be clearly written. You can refer to the following contents

Usage of brackets:

1, a symbol indicating the calculation order, such as () in brackets, () outside brackets.

2. Contrary to the required symbol "","indicates that the content is optional.

In mathematics, it is sometimes used to represent the integer part of a number: let, which means the largest integer that does not exceed. This property can also be used to judge whether a number is even: if it is, it is even, if it is, it is odd.

4. Symbols used to represent character sets in regular expressions.

5. Symbols used to represent array index values in computer languages such as C #, such as arr.

6. Mathematically, it refers to the closed interval of a function, such as (that is, the function domain, which is greater than or equal to the minimum value and less than or equal to the maximum value). =6

In the first, second and third level mixed operations, if you want to calculate the low-level operations first, use parentheses. If: (x+y)z, calculate x+y first; if there are no brackets, calculate yz first and then +X; if you want to widen the brackets, use brackets; if you want to widen the brackets, use braces. Parentheses are calculated first, then parentheses ... Parentheses have priority.