UnitMath is a powerful addition for the Newton MessagePad. It computes formulas anywhere you can write in the Newton OS, making calculations faster and more convenient than ones done using the MessagePad's calculator. However, the real strength of UnitMath comes into play when dealing with equations that involve units. UnitMath recognizes hundreds of units, and automatically converts them, saving you the trouble. It handles uncertainties as well, and lets you know how much you can rely on the answer. It lets the user define variables, and makes repeated calculations easy. There is also a Lite version of UnitMath, for those users who don't need all the features of the full version. If you work with numbers on your Newton OS, UnitMath for you!