Uses 2 types of brackets to indicate values of x(variable) taken in a set, for example:

(2;6) means x values between 2 and 6, excluding 2 and 6

(2;6] means values between 2 and 6, inclusive of 6

[2;6] means values between 2 and 6, inclusive of 2 and 6

We can use inequality signs also;

2<x< 6 means values greater than 2 but less than 6= values between 2 and 6, excluding 2 and 6