Unable to know which number format is used at data entry (e.g. European versus US)

Hi there,
I am new to VBA (using Mac) but developing a small application for use by people from different parts of the world.
I require for instance the exchange rate for the local currency, using a textbox to capture the answer.
I have declared the variable associated with the answer as Currency.

Now comes my problem.
I ask for the format [#,###.####]
Some users however are used yo the European format of [#.###,####] so they accidentally use this.

When I capture the answer in my sheet the result (in case of the European Answer ) to [1,3456] will be [13456] in stead of the expected [1,3456].
If the input has only two digits behind the comma, there is no problem. This problem however occurs with three or more digits.
Is there anyway to prevent this from happening?

When you capture number remove all . and , and after that format it as you like. Does that helps?

But if all . and , are removed, I don't know what the user would have meant.

you get 1.234,567
Remove . you get 1234,567
Substitute , with . you get 1234.567
and now format it as number with #,###.####

Ok I know it is guessing, but if I get 1,234 and the mean 1234 (because they are used to US notation) and not 1.234?
I understand that VBA expects US format. Is there a way to determine what the standard format is on a computer, e.g. ISO code or regional settings on the computer using the app?