In a store last weekend, I saw a simple solar-powered calculator for $2. It had four functions plus a square root key. I'm considering the possibility of buying 50 such calculators and handing them out for use during exams in my freshman calc course, as the only calculators allowed.
No difficulties with determining whether a device is a calculator or a phone, is a graphing calculator, has internet or text-messaging, can do symbolic math, can store notes, ...
In some cases it's sensible to check one's results on calc problems numerically. For instance, I give homework where they differentiate some function and then check themselves numerically by calculating a delta-y/delta x. It would be nice to allow them to use calculators on exams so that they could do the same thing.
Prevents an arms race for students trying to use fancier calculators. Saves students money by eliminating a perceived incentive to buy an expensive calculator that actually has low added utility.
A hassle to maintain the sack full of calculators, replace broken ones, etc.
May mask incompetence in basic arithmetic skills.
Problems would have to be carefully designed so that if a numerical check is required, it stays within the capabilities of the calculators (not so good for transcendentals).
Any problem with a calculator (broken key, ...) becomes my fault.
Has anyone tried this? Is it a good idea?