The symbols 0 through 9 are internationally recognized as numeric values. Many languages have alternative numbering systems and special characters that represent numbers. It would be possible but difficult for an application to custom-process numbers for each language and script. Although it doesn't translate the digits themselves, the Script Manager offers support for formatting a number into a local form. For example, Europeans often use a comma as a decimal point and a period as a thousands marker.
Most countries have unique currency symbols.
There are many different ways to represent numerical values for things such as date, time, and money. This kind of formatting information is in the international resources. One way to do data validation is to use CharType and check for numeric characters. We can't guarantee that this has been implemented for all scripts, but it is correct for Roman and Japanese. NumToString and StringToNum don't deal with international formats.