Feedback form

1 Choose 1

Combination Calculator

What is 1 choose 1?

Answer

1 choose 1 is

1

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

There is exactly one way: take all.

C(1, 1) = 1! / (1! · 0!)

= 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.

Found an error in the calculation or the information?

See Also

Random Number Generator - Pick a random whole number between two bounds
Percent to Probability Converter - Convert Percents to "1 in X" Probability Chance
Factors of a Number - List all Factors and Factor Pairs of a Number

Share This Calculation

Print

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

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

Facebook

Twitter

Telegram

WhatsApp

Viber

Email

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

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

n choose 1 for other n

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

Recalculate with different values ↑

FAQ

What is 1 choose 1?

1 choose 1 is 1

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

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

See Also