My elder son is beginning to enjoy maths! At 12 years old, he is fond of reading, and he has considered several possible future professions, all related with writing and reading: journalist, novel writer, actor, etc. But now that he has enjoyed a good teacher, that makes maths learning fun (basically by giving them homework that is based on investigation: he gives a general problem, and as you solve a question, other questions come that make you think and discover relations and laws by yourself), then he is beginning to enjoy maths.
What he hates (as I did and still do) is the mechanical part of maths. One of the problems of last week was to check which prime numbers below 100 could be expressed as the sum of two squares. While he has learn to check for “prime-ness” by himself, it is tiring to apply it to many numbers. Then I took the opportunity to show him some of the possibilities of the HP Prime CAS mode: the ifactor() function. This function gives the prime factors of an integer; for example, ifactor(60) would return 22*3*5; so, an integer is a prime number if there is a single factor. This speeds a lot the search!
Other concepts that were explained too were gcd and lcm; and it was explained using numbers in its factored form; here he could use the lcm() and gcd() functions once he had apprehended the concepts on the factored numbers, in order to test his results. Then the calculator is really a tool to learn faster, not to cheat on the learning process.
Another alternative that I could have used was the hp50g, or even the hp41cl running any of the Sandmath modules (this is what I use!), but a touch screen is difficult to fight against for a 12 year old kid. The fact that he can download some games written in HP basic helps too. The games are quite lame when compared with what he can get in a simple smartphone; but the beauty of them is that he can enter in the program and try to understand what it is doing; alter number of lives, speed, number of enemies or even their aspect by modifying their grobs; and learn some programming in the process. In that respect, HP basic is much more readable than RPL, and more adequate to write games too.
(For a good load of games for you HP Prime, visit hpcalc.org/prime/games or en.hpprime.club. Some of them are fun enough, and it is surprising how fast can the HP Prime be)