2 choose 1
Choosing 1 from 2— order doesn't matter.
Combinations (order doesn't matter)
2C1 = 2
Permutations (order matters): 2P1 = 2
There are 2 ways to choose 1 items from 2when order doesn't matter, using the formula C(n, k) = n! / (k! · (n − k)!).
2 choose k table
| Expression | Combinations |
|---|---|
| 2 choose 0 | 1 |
| 2 choose 1 | 2 |
| 2 choose 2 | 1 |
Try your own numbers
Need different values? The full permutations & combinations calculator computes nCr and nPr for any n and k.
Frequently asked questions
What is 2 choose 1?+
2 choose 1 equals 2. It counts the number of ways to choose 1 items from 2 when the order does not matter.
What is the formula for 2 choose 1?+
The combinations formula is C(n, k) = n! / (k! · (n − k)!). For 2 choose 1: 2! / (1! · 1!) = 2.