Dix Calculator is a limited calculator program: it limits calculations to combinations of numbers and operations that will guarantee to produce a 10.
For instance, pressing “2” will gray out all the keys except for the “X” operation. Pressing that will highlight “5” as the only available option. Pressing that will highlight “=”, which inturn will produce a predictable results of 10 on the calculator screen.
Dix Calculator is very useful when you need to quickly produce a 10. It's also useful when you don't need to produce a 9.