a = Greenfoot.getRandomNumber(100); //first number
            World world;
            world = getWorld();
            world.showText(""+ a, 100, 200) ;
            
            
            b = Greenfoot.getRandomNumber(100); //second number
            world.showText(""+ b, 300, 200) ;
            
            
            c = (a + b); //answer number
           
            
            Greenfoot.delay(50);
            
            
            String inputValue = JOptionPane.showInputDialog("");
            int d = Integer.parseInt( inputValue );
            world.showText(""+ d, 500, 200) ;
            
            
            if ( d = a + b)
            {
               n= n+1;
            }
            else
            {
                n= 0;
            }
            
            world.showText(""+ n, 500, 300) ;