Yeah Heston, cut this guy some slack. We were all learning once, he may well have been shown how to use the thing properly, but it's easy to tie yourself in knots at first applying the wind the wrong way or whatever, even if you do understand the underlying principle. All he's looking to do is check he's getting the right answer and using the tool correctly, if he finds he is consistently wrong he will obviously go to his instructor for help, but if he's right then he doesn't need to waste his instructors time just for a confidence boost.