ChatterBank2 mins ago
how many combinations of 5 numbers are there from 7 numbers
Can anyone tell me how many combinations of 5 there are from 7 numbers - I think it's 28 but I don't know where I got that from. Any bright sparks with the answer for me (and more importantly, what ARE the combinations or where can I find them on the internet!)
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It should be 21 = 7!/(5! x (7-5)!).
(where 7! = 7 x 6 x 5 x 4 x 3 x 2 x 1, etc.) This assumes order of numbers doesn't matter (1-2-3-4-5 = 5-4-3-2-1)
1 2 3 4 5
1 2 3 4 6
1 2 3 4 7
1 2 3 5 6
1 2 3 5 7
1 2 3 6 7
1 2 4 5 6
1 2 4 5 7
1 2 4 6 7
1 2 5 6 7
1 3 4 5 6
1 3 4 5 7
1 3 4 6 7
1 3 5 6 7
1 4 5 6 7
2 3 4 5 6
2 3 4 5 7
2 3 4 6 7
2 3 5 6 7
2 4 5 6 7
3 4 5 6 7
(where 7! = 7 x 6 x 5 x 4 x 3 x 2 x 1, etc.) This assumes order of numbers doesn't matter (1-2-3-4-5 = 5-4-3-2-1)
1 2 3 4 5
1 2 3 4 6
1 2 3 4 7
1 2 3 5 6
1 2 3 5 7
1 2 3 6 7
1 2 4 5 6
1 2 4 5 7
1 2 4 6 7
1 2 5 6 7
1 3 4 5 6
1 3 4 5 7
1 3 4 6 7
1 3 5 6 7
1 4 5 6 7
2 3 4 5 6
2 3 4 5 7
2 3 4 6 7
2 3 5 6 7
2 4 5 6 7
3 4 5 6 7
1 to 4 of 4
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