Calculator.java

package com.mycompany.test;

public class Calculator{
  public static void main(String[] args){
    int a = 4;
    int b = 2;
    System.out.println(sum(a, b));
    System.out.println(minus(a, b));
  }

  private static int sum(int a, int b){
    return a + b;
  }

  private static int minus(int a, int b){
    return a - b;
  }

  private static int multi(int a, int b){
    return a * b;
  }

  private static int division(int a, int b){
    return a / b; // integrated
  }
}