How does a Math() class method in java works code example

Example 1: math class in java

double roundedDown = Math.round(23.445);
double roundedUp   = Math.round(23.545);
// rounds up and down from float or double

Example 2: math class in java

double random = Math.random();
// chooses random number between 0 and 1 ( * 100 to make it in 100)