If you're anything like me-hell, if you've got anything less than a Ph.D. in combinatorics-you probably have a hard time figuring out how in God's name to put a sum on your MetroCard that doesn't result in your ending up with a wallet full of cards that have 65 cents each on them. Wonder no more! Via the estimable Katie Bakes, please enjoy the MetroCard bonus calculator. And if you see something, say something.

Related: This New Yorker cartoon, which will only be funny to those of you who remember that MetroCards used to be blue.