Name: 【TED-Ed】How many ways can you arrange a deck of cards? - Yannay Khaikin
Uploaded: 2014-04-16T11:42:04.000Z
Duration: 3 min 42 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

The imperative

Actually, just pick up all of them and take a look.

This standard 52-card deck has been used for centuries.

are shuffled in casinos all over the world,

And yet, every time you pick up a well-shuffled deck

that has never before existed in all of history.

The answer lies in how many different arrangements

of 52 cards, or any objects, are possible.

Now, 52 may not seem like such a high number,

but let's start with an even smaller one.

To start off, any of the four people can sit

If we manually write out all the possible arrangements,

that four people can be seated into four chairs,

you can see that each of the four initial choices

leads to three more possible choices for the second chair,

So instead of counting each final scenario individually,

we can multiply the number of choices for each chair:

We start with the number of objects we're arranging,

and multiply it by consecutively smaller integers

So exciting that mathematicians have chosen

As a general rule, the factorial of any positive integer

Fortunately, we don't have to calculate this by hand.

Just enter the function into a calculator,

when the Big Bang is thought to have occurred,

the writing would still be continuing today

ways to arrange this simple deck of cards

So the next time it's your turn to shuffle,