There are a few different ways that you can calculate combinations in Excel. One way is to use the COMBIN function. This function takes two arguments: the number of items and the number of items to choose from. For example, if you wanted to calculate the number of ways to choose 2 items from a set of 5, you would use the following formula:

=COMBIN(5,2)

Another way to calculate combinations in Excel is to use the factorial function. This function takes a single argument - the number of items - and calculates the factorial of that number. For example, if you wanted to calculate the number of ways to choose 2 items from a set of 5, you would use the following formula:

=FACT(5)/(FACT(2)*FACT(3))

You can also use a combination of the COMBIN and FACT functions to calculate combinations. For example, if you wanted to calculate the number of ways to choose 2 items from a set of 5, you would use the following formula:

=COMBIN(5,2)*FACT(2)

There are a few other ways to calculate combinations in Excel, but these are some of the most common methods.