13 Choose 0

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Total items (n)
Items chosen (k)

What is 13 choose 0?

Answer

13 choose 0 is
1

Order doesn't matter, no repeats: 1 way to choose 0 of 13 items.

There is exactly one way: take none.

C(13, 0) = 13! / (0! · 13!)

= 1

0! = 1 (an empty product), so 13! cancels out completely.

Row 13 of Pascal's triangle
k13 choose k
01
113
278
3286
4715
51,287
61,716
71,716
81,287
9715
10286
1178
1213
131

Row sum: 213 = 8,192 — all subsets of 13 items.

See Also

FAQ

What is 13 choose 0?

13 choose 0 is 1

Why is 13 choose 0 the same as 13 choose 13?

Every way to choose 0 of 13 items leaves exactly 13 behind, so choosing 0 and choosing which 13 to leave out are the same count: 13 choose 0 = 13 choose 13 = 1. In the formula n! / (k! (n − k)!) the two factorials below just swap places.

How many ways are there if order matters?

The same 1: with 0 chosen items there is only one order, so P(13, 0) = 13 choose 0 = 1. Order starts to matter from 2 items on: n × (n − 1) arrangements.