### COMBIN(number, number_chosen)

Returns the number of combinations for a given number of items.

 number The total number of items. number_chosen The number of items in each combination.

#### Remarks

* If any of the arguments are not numeric, then #VALUE! is returned.
* If "number" is not an integer, it is truncated.
* If "number" < 0, then #NUM! is returned.
* If "number_chosen" is not an integer, it is truncated.
* If "number_chosen" < 0, then #NUM! is returned.
* If "number" < "number_chosen", then #NUM! is returned.
* A combination is any set or subset of items, regardless of their internal order.
* Combinations are distinct from permutations, for which the internal order is significant.
* If you want to return the number of combinations (with repetition) you can use the COMBINA function.
* For the Microsoft documentation refer to support.office.com

 A 1 =COMBIN(1,1) = 1 = a 2 =COMBIN(2,2) = 1 = ab 3 =COMBIN(3,2) = 3 = ab, bc, ac 4 =COMBIN(4,2) = 7 = ab, bc, cd, dc, ad, bd, ad 5 =COMBIN(5,2) = 10 6 =COMBIN(6,2) = 15 7 =COMBIN(7,2) = 21 8 =COMBIN(8,2) = 28 9 =COMBIN(10,1)*COMBIN(10,1)*COMBIN(10,1) = 1000 10 =COMBIN("8","4") = 70 11 =COMBIN(1,2) = #NUM! 12 =COMBIN("some text",2) = #VALUE! 13 =COMBIN(2,"some text") = #VALUE!

#### Expand ...

1 - How many different 2 person teams can be made up from 8 people. answer 28 teams.
2 - How many combinations are there for a padlock with 3 numbers, answer 1,000 possibilities.