Input.java

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package menucalc;
import java.util.*;

/**
 *
 * @author Josh
 */
public class Input {
    
    public int menuChoice;
    public int choice1;
    public int choice2;
    public int choices[] = {0, 0};
    
    Scanner input = new Scanner(System.in);
    
    public int menuInput() throws InputMismatchException {
        
        System.out.println("Which operation would you like to do?");
        
        menuChoice = input.nextInt();
        
        return menuChoice;
    }
    public int[] chooseNumbers() throws InputMismatchException {
        
        System.out.print("What is your first number? ");
        choice1 = input.nextInt();
        
        System.out.print("What is your second number? ");
        choice2 = input.nextInt();
        
        choices[0] = choice1;
        choices[1] = choice2;
        
        return choices;
   }
}

Math.java

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package menucalc;

/**
 *
 * @author Josh
 */
public class Math {
    
    static int answer;
    static Input Input = new Input();
    
    public static int doAddition(int a, int b) {
        
        return (a + b);
    }
    public static int doSubtraction(int a, int b) {
        
        if (a > b) {
            answer = a - b;
        } else if (a < b) {
            answer = b - a;
        }
        return answer;
    }
    public static int doMultiplication(int a, int b) {
        
        return (a * b);
    }
    public static int doDivision(int a, int b) {
        
        return (a / b);
    }
}

Menu.java

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package menucalc;

/**
 *
 * @author Josh
 */
public class Menu {
    
    Input Input = new Input();
    Math Math = new Math();
    
    public void listMenu() {
        System.out.println("1: Addition");
        System.out.println("2: Subtraction");
        System.out.println("3: Multiplication");
        System.out.println("4: Division");
        System.out.println();
    }
    public void chooseMenu (int a) {
        
        if (a == 1) {
            Input.chooseNumbers();
            System.out.print(Input.choices[0] + " plus " + Input.choices[1] + " equals ");
            System.out.println(Math.doAddition(Input.choices[0], Input.choices[1]));
            System.exit(0);
            
        } else if (a == 2) {
            Input.chooseNumbers();
            System.out.print("The difference between " + Input.choices[0] + " and " + Input.choices[1] + " is ");
            System.out.println(Math.doSubtraction(Input.choices[0], Input.choices[1]));
            System.exit(0);
            
        } else if (a == 3) {
            Input.chooseNumbers();
            System.out.print(Input.choices[0] + " times " + Input.choices[1] + " equals ");
            System.out.println(Math.doMultiplication(Input.choices[0], Input.choices[1]));
            System.exit(0);
            
        } else if (a == 4) {
            Input.chooseNumbers();
            System.out.print(Input.choices[0] + " divided by " + Input.choices[1] + " equals ");
            System.out.println(Math.doDivision(Input.choices[0], Input.choices[1]));
            System.exit(0);
        }
    }
}

MenuCalc.java

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package menucalc;

/**
 *
 * @author Josh Ellis
 */
public class MenuCalc {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        
        //create objects
        Menu Menu = new Menu();
        Input Input = new Input();
        Math Math = new Math();
        
        //show menu choices
        Menu.listMenu();
        
        //take menu choice and send choice to appropriate operation (addition, subtraction, etc.)
        Menu.chooseMenu(Input.menuInput());
    }
}