Java class

Write a program in Java to demonstrate class.

import java.util.*;

abstract class Numbers {
    int no1;
    int no2;
    int no3;
    Scanner s=new Scanner(System.in);
    abstract void calculation();
}
class Add extends Numbers {
    Add() {
        System.out.println("Enter The Nos To Add ->");
        no1=s.nextInt();
        no2=s.nextInt();
    }
    void calculation() {
        no3=no1+no2;
        System.out.println("Addition Is ="+no3);
    }
}
class Sub extends Numbers {
    Sub() {
        System.out.println("Enter The Nos For Subtraction ->");
        no1=s.nextInt();
        no2=s.nextInt();
    }
    void calculation() {
        if(no1>no2)
            no3=no1-no2;
        else
            no3=no2-no1;
        System.out.println("Subtraction Is ="+no3);
    }
}
class Mult extends Numbers {
    Mult() {
        System.out.println("Enter The No For Multiplication->");
        no1=s.nextInt();
        no2=s.nextInt();
    }
    void calculation() {
        no3=no1*no2;
        System.out.println("Multiplication Is ="+no3);
    }
}
class Abstract
{
    public static void main(String[] args) {
        Numbers n;
        n=new Add();
        n.calculation();
        n=new Sub();
        n.calculation();
        n=new Mult();
        n.calculation();
    }
}

Output

Enter The Nos To Add ->
40
20
Additon Is =60
Enter The Nos For Substraction ->
40
20
Substraction Is =20
Enter The No For Multiplication->
2
3
Multiplication Is =6