10 Choose 7

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

What is 10 choose 7?

Answer

10 choose 7 is
120

Order doesn't matter, no repeats: 120 ways to choose 7 of 10 items.

Choosing 7 of 10 is the same as leaving 3 out: C(10, 7) = C(10, 3).

C(10, 7) = 10! / (7! · 3!)

= C(10, 3)

= (10 × 9 × 8) / (3 × 2 × 1)
= 720 / 6

= 120

If order matters (permutations): P(10, 7) = 10 × 9 × 8 × … × 4 = 604,800 — each combination in 7! = 5,040 orders.

Row 10 of Pascal's triangle
k10 choose k
01
110
245
3120
4210
5252
6210
7120
845
910
101

Row sum: 210 = 1,024 — all subsets of 10 items.

See Also

FAQ

What is 10 choose 7?

10 choose 7 is 120

Why is 10 choose 7 the same as 10 choose 3?

Every way to choose 7 of 10 items leaves exactly 3 behind, so choosing 7 and choosing which 3 to leave out are the same count: 10 choose 7 = 10 choose 3 = 120. In the formula n! / (k! (n − k)!) the two factorials below just swap places.

How many ways are there if order matters?

P(10, 7) = 604,800. Each of the 120 combinations can be put in order in 7! = 5,040 ways, so permutations = combinations × k!: P(n, k) = n! / (n − k)!.