Mr. Cedric Moonen :) bellow is the code that l did compile and it works perfectly..thanks alot.. public class Calculate { public static void main(String[] args) { double x,y; if (args.length == 3) { x = Double.parseDouble(args[0]); y = Double.parseDouble(args[2]); if(args[1].equals("+")) { System.out.println("Answer = "+ (x + y)); }else if(args[1].equals("-")) { System.out.println("Answer = "+ (x - y)); }else if(args[1].equals("/")) { System.out.println("Answer = "+ (x / y)); }else if(args[1].equals("x")) { System.out.println("Answer = "+ (x * y)); } }else System.out.println("Do it again......"); } }