Source: The Game Website. TwentyFour is an addictive new iPhone game based on a classic math card game! Use the four given numbers with +, -, x and ÷ to make 24. Hours of fun! Great for keeping your mind sharp with mental math! Test your skills today! Features: Timed play - race against the clock! Free play - try to solve them all! Peer to peer - challenge a friend! Online single and multi-player high scores Solutions available if you get stuck. Available for the iPhone and iPod Touch Highly addictive and fun!