Play: Tap on a question on the left-hand side of the screen of the iPad or the "Ask" tab of the iPhone version to receive a clue about the mystery number. The clue will appear on the right-hand side of the screen on iPad and the "Clues" tab on iPhone. When you think you know the number, or would like to take a guess, type your answer into the "What's your answer -- incorrect answers cost" box in the middle of the screen. Then press return. If you are correct, your score will be displayed. If your guess is incorrect, you can continue to play and make another guess but your guesses will cost you!

Scribble: A space provided for writing your notes and guesses.

Calculator: A place to quickly make calculations.

Hint: A place where you can look to see if you have made a mistake in calculations or if you need help seeing what you know.

Settings: Here you can start a new game if you are already in the middle of one and reset all of your past high scores. You can also choose to to turn "Play Until You Win Mode" on. In this mode the game will not end until you guess the correct number, no matter how bad your score is. With this mode off, the game will end if you have filled up the pie chart, but did not guess the correct number on your last guess. You can also turn on and off sounds and adjust volume.

Scoring: Each question you tap on will cost a different amount based on how much information the buttons may reveal. For example, a button revealing the sum of the digits of the mystery number will most likely give far more information than the button telling whether or not the mystery number is a perfect square. The score will be displayed by a colored pie chart on the right-hand screen of the game. Each time you tap on a question, a section of the pie chart will turn black. The amount of the chart that becomes black will reflect the "cost" of the button clicked. Also, a section of the pie chart will become black if you type in a wrong guess/answer. Once the chart is completely black, you will receive the answers to all the rest of the buttons. If you are not in "Play Until You Win Mode" you will then be allowed to make one more guess, but your score be zero or less. If your guess is correct, you will win, but if it is incorrect, the game will end and you will be told the answer. This is the default mode. If you are in "Play Until You Win Mode", you will be allowed to continue to make guesses until you win the game by inputting the correct number.