Distributive property

分配律，聯想和交換

You can use the buttons on the left to listen and display a concept: parentheses, distributive, commutative, associative, addition inverse and multiplicative inverse.

The button of PROBLEMS generates a random question.

You can use the big button on the bottom of the screen. After pressing it, say a command. They have the same name as the buttons.

Say the word help for hearing of all valid commands.

The answers can be given using the same button. First, press the big button, then you can pronounce the answer.

There are commands that can be use it only by VOICE:

SCORE to set it to zero.

AUTHOR provides information about the author and his last applications.