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1 Choose 0

Combination Calculator

What is 1 choose 0?

Answer

1 choose 0 is

1

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

There is exactly one way: take none.

C(1, 0) = 1! / (0! · 1!)

= 1

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

Row 1 of Pascal's triangle
k	1 choose k
0	1
1	1

Row sum: 2¹ = 2 — all subsets of 1 item.

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https://calculat.io/en/number/combinations/1--0

<a href="https://calculat.io/en/number/combinations/1--0">1 Choose 0: Combinations C(1, 0) - Calculatio</a>

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1 Choose 0: Combinations C(1, 0). 1 choose 0 = 1: the number of ways to choose 0 of 1 item when order doesn't matter and nothing repeats.

https://calculat.io/en/number/combinations/1--0/generated.jpg

n choose 0 for other n

n choose 0	Answer
1 choose 0	1
2 choose 0	1
3 choose 0	1
4 choose 0	1
5 choose 0	1
6 choose 0	1
7 choose 0	1
8 choose 0	1
9 choose 0	1
10 choose 0	1
11 choose 0	1
12 choose 0	1
13 choose 0	1
14 choose 0	1
15 choose 0	1

Recalculate with different values ↑

FAQ

What is 1 choose 0?

1 choose 0 is 1

Why is 1 choose 0 the same as 1 choose 1?

Every way to choose 0 of 1 item leaves exactly 1 behind, so choosing 0 and choosing which one to leave out are the same count: 1 choose 0 = 1 choose 1 = 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(1, 0) = 1 choose 0 = 1. Order starts to matter from 2 items on: n × (n − 1) arrangements.

See Also