我这个代码里面 / 没用，应该怎么做呀？求大佬解答

public class HelloWorld{

    public static void main(String[] args) {

    int one = 10 ;

        int two = 20 ;

        int three = 0 ;

        three = one+tow;

        System.out.println("three = one+two ==>"+three);

        three += one;

         System.out.println("three += one ==>"+three);

         three -= one;

          System.out.println("three -= one ==>"+three);

          three *= one;

           System.out.println("three *= one ==>"+three);

           three/=one;

            System.out.println("three /=one ==>"+three);

            three %=one;

             System.out.println("three %=one ==>"+three);

}

}