Sure, they're a racket. But they're also a handy tool.
You can plug in a bunch of arithmetic, and it just does it, but you can easily edit and redo. They can graph some functions, and do some of the brute force stuff (like newton's method etc), so you can concentrate on the thinking.
If you spend the class time writing a program to solve the homework, instead of doing the homework, you've practiced a life skill and probably understand the material pretty well.
If you get the 68k based calculators (ti-92 and ti-89), they've got a symbolic algebra system and can do a lot of cool stuff, although giving that to a high schooler may not be the best choice.
You can plug in a bunch of arithmetic, and it just does it, but you can easily edit and redo. They can graph some functions, and do some of the brute force stuff (like newton's method etc), so you can concentrate on the thinking.
If you spend the class time writing a program to solve the homework, instead of doing the homework, you've practiced a life skill and probably understand the material pretty well.
If you get the 68k based calculators (ti-92 and ti-89), they've got a symbolic algebra system and can do a lot of cool stuff, although giving that to a high schooler may not be the best choice.