Texas Instruments TI25X SOLAR Calculator

The best thing about the TI-25X is its size. It's small and thin enough to easily slip into a jeans pocket, and the hard plastic cover that conforms to either the front or back of the unit will keep the calculator safe in transit. The rubber keys appear to be very durable and respond crisply to input. The keypad is a little cramped, but the high-contrast white and orange lettering is easy to read in all sorts of lighting conditions. Speaking of lighting, this is a true solar device--there's no battery to fall back on--but it performed well even in extremely dim conditions.

Any calculator in this price range has some caveats, and the biggest fault we could find with the TI-25X was its display. It is tiny, it only handles a maximum of eight digits (most calculators can display 10 to 12), and it is a single-line display instead of a more useful two-line design. We also had a hard time accepting the skimpy folded sheet of paper that comes with the calculator as adequate documentation, especially since it includes few examples and is awkward to use. If you can deal with those drawbacks, the TI-25X is a decent entry-level scientific calculator, and an excellent choice if you just want a very small device at a rock-bottom price. --T. Byrl Baker

Pros:

• Very portable
• Durable design
• Labels are exceptionally easy to read

Cons:

• Can't handle two-variable statistics
• Lacks some of the advanced features of other products in this price range, like a two-line display

The TI25X Solar runs on solar power so you'll never have to worry about low battery power or changing batteries. It includes a protective slide cover.