This is a simple “Variable” example.

public class VariableExample {
 
     public static void main(String[] args) {
 
          double a;
          double b;
          double sum;
          double difference;
          double division;
          double multiplication;
 
          a = 3;
          b = 4;
 
          sum = a + b;
          difference = a - b;
          division = a / b;
          multiplication = a * b;
 
          System.out.println("a + b = " + sum);
          System.out.println("a - b = " + difference);
          System.out.println("a / b = " + division);
          System.out.println("a * b = " + multiplication);
     }
}