Go4Expert - Question about how to change my program to user change the input of rate by user

Code:
/**

 * @(#)MathDemo.java

 *

 * MathDemo application

 *

 * @author

 * @version 1.00 2012/4/23

 */

//import java.util.Scanner;

public class MathDemo {



    public static void main(String[] args) {

                //rate is the value of hourly pay

        //        Scanner in = new Scanner(System.in);

            double rate = 80.00;

            System.out.println("value of rate is " + rate);



            //pay is value of weekly pay

            double pay = 40 * rate;

            System.out.println("the value of pay is " + pay);



            //anualPay is the value of a year's work

            int bonus = 100;

            double annualPay = pay * 12 + bonus * 12;

            System.out.println("annual salary is $ " + annualPay);





//sorry guys im lost on how I suppose to change rate to be input by the user pleeasy help //:)



    }

}