Quick Maths was never so fun!
If the cards played equal more than 21... BURST! This is where quick maths is important and you want to hold onto higher value cards, but you have to play SOMETHING. Push it as close to 21 as you can and hope your opponent has no other options.
Pull cards to gain points. Play cards to trap your opponents and force their hand. As the pressure mounts will your cards hold up or blow up?