This book is written for the person who's either tried other ways and can't get to grips with Java. Or someone who wants to know how to write a program that will ask for an input, do some calculations and give some answers. It was written because I'm dyslexic and read loads of books and found they didn't help me. Also I tend to learn by example and all the books and examples I found seemed to be based around programing the answer in a database and selecting it each time. None of them worked anything out. I went on Bulletin Boards and asked questions but most thought I was a student trying to get my homework done for me! So I'm now at the point where I know this bit of code and what it can do and thought I ought to share it as there must be others in the same position.
This is not going to teach you everything about Java, it will just give you a start if you're interested in making it do the work for you.
It contains examples that will work out areas, circumferences of circles, boundary lengths, hypotenuse, angles and area of right-angled triangles and circumference, shoulder height, revolutions per mile/Km and virtual axle height for given radial tyre/tire size. You can take these and make them work for you.