10, it's minus 1, counts plus 15.

Five, that counts 16.

This is a scene from the 2008 film 21.

An MIT student is playing Blackjack at a casino in Las Vegas.

He's assigning a value to each card that hits the table

and he's keeping a running count in his head that somehow gives him an advantage.

Jack plus 12, 9 still plus 12.

Black Jack.

He uses this system to rack up hundreds of thousands of dollars in winnings until the

casino notices his hot streak. At that point security guards take him into a

back room, beat him up, and threaten to kill him if he ever comes back.

That movie was very loosely based on the story of the MIT Blackjack team.

A group of students and recent graduates who taught themselves the technique known as counting cards.

In movies like 21, card counters are often portrayed as mathematical savants who rob casinos

blind until they're caught.

Casinos have bought into this mythology.

They've taken drastic measures to stop card counting.

But those measures have come at a steep cost.

A lot of the casinos spend so much time and effort to try to detour card counting.

They actually cut their own throats.

They're pressing away their dollars to try to save pennies.

For the Freak economics radio network,

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