"Missing number, treated as zero." in LaTex

Question

I want to get the Roman number of 2. So I use $\Roman{2}$ inside text. But then I got an error

Missing number, treated as zero.

How can I fix it?

Thanks and regards!

Answer 1

I think you mean \Roman not \Rome. Anyway, \Roman prints the value of a counter as a roman numeral, so you can't use it with "2".

Short answer - use \romannumeral 2.

Long answer - define commands as described here.