<p>What's the difference between <code>Char.IsDigit()</code> and <code>Char.IsNumber()</code> in C#?</p>

I found the answer:
Char.IsNumber() determines if a Char
  is of any numeric Unicode category.
  This contrasts with IsDigit, which
  determines if a Char is a radix-10
  digit.
Valid numbers are members of the
  following categories in
UnicodeCategory
:
```
DecimalDigitNumber
```
Decimal digit character, that is, a character in the range 0 through 9. Signified by the Unicode designation "Nd" (number, decimal digit). The value is 8.
```
LetterNumber
```
Number represented by a letter, instead of a decimal digit, for example, the Roman numeral for five, which is "V". The indicator is signified by the Unicode designation "Nl" (number, letter). The value is 9.
```
OtherNumber
```
Number that is neither a decimal digit nor a letter number, for example, the fraction ½. The indicator is signified by the Unicode designation "No" (number, other). The value is 10.
Conclusion
```
Char.IsDigit
```
:
Valid digits are members of the
```
DecimalDigitNumber
```
category only.
```
Char.IsNumber
```
:
Valid numbers are members of the
```
DecimalDigitNumber
```
,
```
LetterNumber
```
, or
```
OtherNumber
```
category.