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    9 Choose 1

    Combination Calculator
    Total items (n)
    Items chosen (k)

    What is 9 choose 1?

    Answer

    9 choose 1 is
    9

    Order doesn't matter, no repeats: 9 ways to choose 1 of 9 items.

    C(9, 1) = 9! / (1! · 8!)

    = 9 / 1

    = 9

    Row 9 of Pascal's triangle
    k9 choose k
    01
    19
    236
    384
    4126
    5126
    684
    736
    89
    91

    Row sum: 29 = 512 — all subsets of 9 items.

    See Also

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    https://calculat.io/en/number/combinations/9--1Copy
    <a href="https://calculat.io/en/number/combinations/9--1">9 Choose 1: Combinations C(9, 1) - Calculatio</a>Copy
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    9 Choose 1: Combinations C(9, 1). 9 choose 1 = 9: the number of ways to choose 1 of 9 items when order doesn't matter and nothing repeats. C(9, 1) = 9 / 1.
    https://calculat.io/en/number/combinations/9--1/generated.jpgCopy

    n choose 1 for other n

    n choose 1Answer
    2 choose 12
    3 choose 13
    4 choose 14
    5 choose 15
    6 choose 16
    7 choose 17
    8 choose 18
    9 choose 19
    10 choose 110
    11 choose 111
    12 choose 112
    13 choose 113
    14 choose 114
    15 choose 115
    16 choose 116
    Recalculate with different values ↑

    FAQ

    What is 9 choose 1?

    9 choose 1 is 9

    Why is 9 choose 1 the same as 9 choose 8?

    Every way to choose 1 of 9 items leaves exactly 8 behind, so choosing 1 and choosing which 8 to leave out are the same count: 9 choose 1 = 9 choose 8 = 9. In the formula n! / (k! (n − k)!) the two factorials below just swap places.

    How many ways are there if order matters?

    The same 9: with 1 chosen item there is only one order, so P(9, 1) = 9 choose 1 = 9. Order starts to matter from 2 items on: n × (n − 1) arrangements.

    See Also