unicode numbers Mac

Mac OS X:
Working with an XML document containing numeric character entities and want to know what they represent? Display any Unicode character your system fonts can display by entering its numeric value, and display characters that are plus or minus any offset you want by doing addition or subtraction

Go to "View - Display Format - Unicode" from the menu.
If you had a numeric value in the previous display, it will be replaced by the equivalent Unicode character. You can display different characters by hitting the Clear button and then entering a new value. (The display will update each time you enter a numeral, since the calculator has no way of knowing whether you're going to enter a 2-digit, 3-digit, 4-digit or whatever value.) You can do Unicode math by hitting the + or - button and entering a value; the display will update to the appropriate offset from the character in the display.

This works for hexadecimal, too, if you start out with the hex
calculator.

(Thanks, David Sewell, for the tip.)