# COMBIN

The `COMBIN` function calculates the number of combinations for a given number of items. A combination is a way of selecting items from a larger set where order does not matter. This function is commonly used in probability and statistics.

## Usage

Use the `COMBIN` formula with the syntax shown below, it has 2 required parameters:

Parameters:
1. n (required):
The total number of items to choose from.
2. k (required):
The number of items to choose from the total.

## Examples

Here are a few example use cases that explain how to use the `COMBIN` formula in Google Sheets.

### Choosing a Committee

If a group of 10 people are running for a committee and 5 need to be chosen, `COMBIN(10,5)` would give the number of possible combinations of committee members.

### Poker Hands

In poker, a hand is a combination of 5 cards. `COMBIN(52,5)` would give the number of possible unique poker hands.

If a password is 8 characters long and can contain uppercase letters, lowercase letters, and numbers, `COMBIN(62,8)` would give the number of possible password combinations.

## Common Mistakes

`COMBIN` not working? Here are some common mistakes people make when using the `COMBIN` Google Sheets Formula:

### Incorrect order of arguments

Make sure to enter the n value first and the k value second, otherwise the formula will not work correctly.

### Using non-numeric values

COMBIN only works with numeric values, so make sure to enter numbers for n and k. If you enter text or other non-numeric values, the formula will return an error.

### Entering a negative value for n or k

COMBIN only works with positive values for n and k. If you enter a negative value for either of these arguments, the formula will return an error.

### Using decimal values for n or k

COMBIN only works with whole numbers for n and k. If you enter a decimal value for either of these arguments, the formula will round down to the nearest whole number.

### Incorrectly calculating combinations

Make sure you understand the formula for calculating combinations before using COMBIN. The formula is n! / (k! * (n - k)!), where n is the total number of items, and k is the number of items you want to choose. If you enter the wrong values for n and k, you will get the wrong result.

The following functions are similar to `COMBIN` or are often used with it in a formula:

• `PERMUT`

The `PERMUT` function returns the number of permutations of a set of objects. A permutation is a way of arranging objects in a specific order. The function takes two arguments: `n`, the total number of objects, and `k`, the number of objects to arrange. The result is the number of possible permutations. This function is commonly used in combinatorics and probability theory.

• `BINOMDIST`

The `BINOMDIST` function calculates the probability of a certain number of successes in a fixed number of trials given a constant probability of success for each trial. This function is commonly used in statistical analysis and hypothesis testing.

• `RAND`

The `RAND` function returns a random number between 0 and 1. This function is often used in combination with other functions to generate random values for simulations, games, or statistical analysis.

• `SUM`

The `SUM` function in Google Sheets adds up a range of numbers. This function is most commonly used to sum the values in a range of cells.

• `COUNT`

The `COUNT` formula returns the number of numeric values within a specified range of cells. It is commonly used to count the number of entries in a given range that meet specific criteria, such as counting the number of sales above a certain threshold.

You can learn more about the `COMBIN` Google Sheets function on Google Support.