A program to train children's mathematical skills in the four calculation
methods: addition, subtraction, multiplication and division.

The preferences allow to adapt the difficulty to any pupil's level, from basic
primary (elementary) school to secondary and beyond. Possible changes include:

* maximum of operands or result,
* integer or decimal (with up to four decimal places) operations,
* with or without carry over,
* multiplication and addition tables training,
* number of authorized tries,
* and some few others...

The program also gives hints when the given answer is wrong (send your tips to
the author, if you have some more!). For advanced users, there is a timer -- but
it is shut-off by default, as to not stress sensible children.

The challenge mode (reachable from the menu in the first dialog) allows children
to play against themselves and others with predefined challenges and a
high-scores list.

Finally, the language of the app can be set differently (English, French,
German, Italian, Spanish) from the system default.