Math.Random is used to produce random numbers. Review the code sample below:
Java Code: 
// producting random number int he range between 0 - 10
System.out.println(Math.random()*10);

// producting random number int he range between 0 - 100
System.out.println(Math.random()*100);

// producting random number int he range between 0 - 1000
System.out.println(Math.random()*1000);

// producting random number int he range between 0 – 10000
System.out.println(Math.random()*10000);