Here's another homework-type question, converting UK pounds to the various imperial weights and finally to kilograms. Again, this probably isn't 100% perfect, but it does the job.
Java Code:
/**
 * This will convert imperial measurements relating to weight
 * to the metric equivalent. Please see
 * the methods at the bottom of the code to see how the
 * conversion is done. Note: Some of the calculations might
 * not be perfect when checked against an online calculator
 * but no online solution posted in a forum should be
 * considered perfect, so it's up to you to refine the code
 * if you think that is required.
 * 
 * @author: Shaun B
 * @version: 2012-10-29
 **/
import java.lang.Math;
import java.util.Scanner;
public class exerciseTwo
{    
    // This is a constant available at a class level
    private static final float kilosPerPound = (float) 0.45359;
    // This is a class level variable (privately declared) which will be
    // used within the main method and any other methods that require it:
    private static int pounds = 0;
    // This will read in our keyboard inputs via the Scanner utility:
    private static Scanner keyboardInput = new Scanner(System.in);
    // This will tell the main routine to continue running:
    private static boolean run = true;
    // Here is the main method, ie, where it runs from:
    public static void main(String[] args)
    {
        System.out.println("This will demonstrate converting imperial weights (Pounds");
        System.out.println("and ounces) to metric weights. Please enter the number of");
        System.out.println("the number of pounds you wish to convert as a whole number");
        System.out.println("or enter 0 (zero) to exit this demonstration.");
        while(run)
        {
            System.out.print("C:\\>");
            try
            {
                pounds = keyboardInput.nextInt();
            }
            catch(Exception e)
            {
                System.err.println("Illegal keyboard entry in main class");
                run = false;
                System.exit(0);
            }
            if(pounds == 0)
            {
                System.out.println("Goodbye!");
                run = false;
                break;
            }
            System.out.println("Here is the conversion:");
            System.out.format("%d is %f ton(s)\n",pounds,tons(pounds));
            System.out.format("%d is %f hundredweight\n",pounds,hundredWeight(pounds));
            System.out.format("%d is %f quarter\n",pounds,quarter(pounds));
            System.out.format("%d is %f stone\n",pounds,stone(pounds));
            System.out.format("%d is %d ounces\n",pounds,ounces(pounds));
            System.out.format("%d is %d drachm\n",pounds,drachm(pounds));
            System.out.format("%d is %d grains\n",pounds,grain(pounds));
            System.out.format("%d is %f kilograms\n",pounds,kilograms(pounds));
        }
        System.exit(0);
    }
    public static float tons(int x)
    {
        return (float)x/2240;
    }
    public static float hundredWeight(int x)
    {
        return (float)x/112;
    }
    public static float quarter(int x)
    {
        return (float)x/28;
    }
    public static float stone(int x)
    {
        return (float)x/14;
    }
    public static int ounces(int x)
    {
        return x*16;
    }
    public static int drachm(int x)
    {
        // A drachm is 1/256 pounds, so we can call the ounces
        // method above and multiply that by 16, as 16 is the
        // square root of 256:
        return ounces(x)*16;
    }
    public static long grain(int x)
    {
        return (long)x*7000;
    }
    public static float kilograms(int x)
    {
        return (float)x*kilosPerPound;
    }
}


Feel free to ask any questions,

Shaun.