MaTris is a nice program for practicing the basic operations of arithmetic. The calculation  method is preselectable. It includes simple counting exercises, addition with symbols, addition/subtraction with different number  ranges, and multiplication/division with defined factors. One can thus train different  learning skills. A solution button shows the correct result; optional sound effects provide  audio feedback. After solution of a predefined number or time of exercises, the child may play  a tetris-like game. The more exercises solved, the more points will be received in the game  part. Multilingual version: German, English, Swedish, Italian, Spanish, French, Norwegian.