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How to use FACTDOUBLE function in Excel spreadsheets [Tip]

This post [1] covered the FACT Excel function that you can find factorials with. You can also find double factorials with Excel 2010/13. The double factorial is the product of all integers from one up to a non-negative integer n with the same parity as n. For example, the double factorial of 8 is 8 x 6 x 4 x 2, which is 384. You can find the double factorial with the FACTDOUBLE function.

For example, enter 8 in an Excel spreadsheet cell. Select a cell to add the function to, and click the fx button beside the formulae bar. Then you should select FACTDOUBLE from the Insert Function window.

factdouble [2]

Then press the button beside the Number field. Select the cell that you entered 8 in. Then press OK to add the FACTDOUBLE function to spreadsheet cell. It will return a value of 384, which is the double factorial of eight.

factdouble2 [3]

You can also enter this function directly into the formulae bar. Select the bar and enter = FACTDOUBLE. Beside that input the value to find the double factorial for in brackets and press Enter. So the formula could be =FACTDOUBLE(8).

So that’s how you can add the FACTDOUBLE function to Excel 2010/13 spreadsheets. This page [4] includes a video that also shows you how to add the function to Excel spreadsheets.