If Google and other technology tools are dulling our intelligence by putting answers right at our fingertips, calculators are worse—they're the original culprits. But now, there's a calculator that makes you work for the answers. Ilan Samson, an "inventor-in-residence" at the University of California, San Diego, has unveiled the QAMA calculator, a tool that only reveals answers if users first provide it with a reasonable mental estimate.

"The purpose of QAMA is to bring back the full involvement of the mind without having to give up the virtues of the calculator," Samson says. "There is very little use in doing things that do not involve understanding. Students have been increasingly trained to perform correctly without necessarily understanding what they're doing and why."

The calculator is available both as a handheld device and a web-based application (at www.qamacalculator.com). Users can perform simple arithmetic or complex scientific calculations, but they must have a basic understanding of the formulas they are attempting to apply. According to cognitive scientists, solving a problem this way helps us understand and remember formulas better than if the answers were automatically supplied to us.

"This is a rare case of a product with absolutely nothing else like it on the market, and yet no one has any doubt about why it is badly needed," Samson says.