Many adults think it's strange that students can use calculators in math class at all, so it's hardly surprising that many of them have trouble selecting the right calculators for their kids.

What do you get for an extra $20, or an extra $50?

Does it make sense to buy a calculator your child can grow into?

Indeed, a savvy parent can buy a calculator that will last a child from middle school to college.

"Many of today's calculators are really handheld computers," said Eileen Shihadeh-Shald of Texas Instruments' educational technology division. "You can download new programs as your children move on to new classes."

Parents should check with schools before buying anything. Some districts and teachers require specific models. Some schools provide calculators for class and home use, others don't.

And if you still hate the idea of your kid using a calculator rather than learning math the old-fashioned way, relax.

Studies consistently show that graphing calculators provide kids with the concrete examples they need to understand the abstract theory they learn in class.