In Excel, if you have text that represents a number that is not recognized as a number value some Excel formulas may not work correctly.
In order to convert a text number into a number value you have a few options.
Convert text to number
First, you can just multiply the value by 1. This will force the conversion of the text into a numerical value and return the equivalent numerical value.
=A1*1
Next, you can use the VALUE formula. You wind up with the same result.
=VALUE(A1)
Convert Roman Numeral text to number
If your text is a Roman Numeral you can convert that to an equivalent numerical value (in decimal). Excel 2013 introduces a function called ARABIC that will convert roman numerals into decimal value equivalents.
If you don’t have Excel 2013, you can use the pwrARABIC function available in the Excel PowerUps Premium Suite addin. The example below returns the value 1920.
=pwrARABIC(“MCMXX”)
Get the free addin
Overall, there are about 50 new worksheet functions in Excel 2013. The addin linked below adds 46 of the 50 functions so your legacy version of Excel can have most of the worksheet function capability of the 2013 version.
https://officepowerups.com/downloads/excel-powerups-premium-suite/
There you go.