This is a calculator that also has a tip calculator and converters for Celsius and Fahrenheit, millimeters and inches, centimeters and inches, feet and meters, quarts and liters, milliliters and quarts, kilometers and miles, pounds and kilograms, grams and ounces, and milligrams and grams.
The user interface is very simple and quick to use when you need to figure something out. Weather you are in a restaurant and trying to figure out the tip with the bill quick and easy or watching an international TV station and trying to figure out the metric or USA measurements or just international traveling.
The calculator alone is easy to use with common calculations and is also the keyboard for the tip calculator and the converters.
The interface buttons have Betsy Blue the Big Horn Sheep ewe on them and makes for a graphical app experience.