1, indicating the order of calculation.

Parentheses and other parentheses (parentheses "()" and braces "{}") indicate the order of expression operations. If an expression has the above three kinds of brackets at the same time, it is generally necessary to calculate the formula in brackets first, then the formula in brackets, and finally the formula in braces.

2, said "integer function"

The general form of integer function is "y=[x], x∈R", and its function value "y" is equal to the largest integer not exceeding "x". The integer "rounding" value is the integer value itself.

3 indicates a closed interval.

The closed interval "[a, b]" can be expressed by set equivalence as "{x∈R|a≤x≤b}". "[a, b]" can be read as "closed interval A to B", which refers to the value range (or set) formed by all real numbers (note: including endpoints A and B) between A and B.

4. Other usages

Representation matrix. Represents the least common multiple of two positive integers. Such as: [4,6] =12.

definition

Brackets, also called square brackets, are a kind of brackets. Besides being an auxiliary symbol of operation, it has other functions in mathematics. For example, it can be used to represent the least common multiple of two integers, such as [15,21] =105.

The bracket "()" or parentheses appear in 1544, and the bracket "[]" or bracket, brace "{}" or curly braces were introduced by the mathematician David in 1593, which were produced in order to meet the needs of the operation of multiple quantities.