I'm trying to learn navigation. I have only a few examples in my textbook. I would love to find some quizzes where they lay out the questions and you calculate and check your answer, but I am not finding any such web sites. I am trying to be as exact as I can, but notice that my answers can differ from the solution by one or two degrees heading, and a few knots difference (one or two or even more) in ground speed. This is the case if I use a ruler and protractor or else the eb-6 variant. My question is, is this good enough? Some problems from the book I have redone several times, but I don't know how exact the PPL questions expect one to be. I had a similar problem with takeoff distances and fuel consumption using those fuzzy POH diagrams, but there I understood that it was the diagrams. Here I would expect to get the same exact answers, but I always am a little off. Is this normal?