Success with computers like the Rpi requires logical thinking and nothing trains a kid for that better than math. I have a degree in math and so am always on the lookout for ways that introduce math and make it more understandable to kids.
A while back in the US there was a popular show about kids called The Wonder Years. The actress Dancia McKellar who played the hero's sort-of girl friend has since written a number of books on math for kids:
What has brought this all to mind is the recent release of a bestselling Japanese schoolgirl novel in English translation called Math Girl. It's the natural combo of mathematical rigor and light romance....
The PDF of the first two chapters looks pretty good to me:
As an aside, I have read a lot of books in recent years on prime numbers and have been totally seduced (like so many others since the mid-1800s) by the mysteries of the Riemann Hypothesis and the Zeta Function. This problem is the most important riddle in math and there is a million dollar prize at the Clay Foundation waiting for the first person that solves it.
If there is a Secret To The Universe, somehow it is in the Zeta Function. Endless levels of prime numbers aren't showing up in atomic quantum spectra from the lab by accident. Now there's even a Rpi-style effort starting up to solve it:
Maybe someday a math girl will use a Rpi to calculate a Riemann Zero counterexample way out there on the number line and so come up with the greatest discovery since relativity. That would be nice.