Numbers are stupid in this case

import java.util.Scanner;

public class Main {

    public static void main(String[] args)
    {
        Scanner keyboard = new Scanner(System.in);
        // set up Scanner for keyboard input


        // Read in phone number
        System.out.println("Enter a 10-digit phone number without spaces");
        long fullPhone = keyboard.nextLong();

        // Find area code part
        long areaCode;
        areaCode = fullPhone / 10000000;

        // Find last 4 digits
        long lastFour = fullPhone % 10000;
        //fullPhone = 10000 - exchange;

        // Find exchange part
        long exchange;
        //phoneMinusAreaCode :=
        exchange = (fullPhone - (areaCode * 10000000) - lastFour)/10000;


        // Print original, plus new number all formatted
        System.out.println("Original number entered: " + fullPhone);
        System.out.println("Phone number formatted: ("+ String.format("%03d", areaCode) + ")" + String.format("%03d", exchange) + "-" + String.format("%04d", lastFour));
    }

}