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 //:)

    }
}