You have the following options:
COMPARING positive and negative numbers (rules)
ABSOLUTE VALUE description.
ADDITION signed numbers.
SUBTRACTION rules with signed numbers.
MULTIPLYING rules.
DIVIDING rules.
SCORE set to zero your counter.
PROBLEMS generates a random question.
CHECK you must press this button to know if your answer is right. First, the answer must be written in the space beside CHECK.
VOICE The big button of the bottom of the screen allows you to select your option and give your answer using your voice. The voice recognition feature only can be used with an active internet connexion.
HELP, only can be used with VOICE, allows you listening all the voice commands.
AUTHOR, gives information about the author.