"This extraordinary work takes the reader on a long and fascinating journey--from the dual invention of numbers and language, through the major realms of arithmetic, algebra, geometry, trigonometry, and calculus, to the final destination of differential equations, with excursions into mathematical logic, set theory, topology, fractals, probability, and assorted other mathematical byways. The book is unique among popular books on mathematics in combining an engaging, easy-to-read history of the subject with a comprehensive mathematical survey text."
If asked, I tend to direct people towards the following books:
http://www.amazon.com/The-Art-Electronics-Student-Manual/dp/...
Note: you need both the student manual (which most people don't know exists) and The Art Of Electronics.
To cover the maths background required, I recommend:
http://www.amazon.com/Mathematics-Birth-Numbers-Jan-Gullberg...
They are not cheap but worth it.
Oh and a calculator. Any old cheap scientific (Casio/TI/HP) will do as long as it doesn't make errors.
The big problem for me was the maths initially. It doesn't take long before you hit a brick wall at the age of 12. My 10 year old daughter is learning algebra and programming (in python!) though at school so things are looking up.
It's better than anything I've read from any mathematician. They seem to forget that people don't know what they are talking about to start with.
http://www.amazon.com/Mathematics-Birth-Numbers-Jan-Gullberg...
It's filled with a lot of history on why things are as they are and it builds up a substantial base of math knowledge from there. I can't comment on whether the additional background information would help someone who is math shy to "get it" but, from the parts I read, it certainly rounded out (and expanded) my knowledge.
I'm pretty sure the result would be the utter destruction of my productivity for a few years.