In addition to the usefulness of the alt key, (I use it a lot when I don't feel like using the equation editor, or if I'm typing some math equation on the forums and need a squared, e.g., x² + x³ (alt 0178 and alt 0179)
The thing that's really bugged me though - WHY??! WHY doesn't this work for the regular number row??? If you hold down the alt key and use the regular number row, nothing happens. Who came up with that as a standard. "Hey, we'll allow them to insert other characters using the alt button, but ONLY if they have a numeric keypad on their keyboard. God forbid we allow them to use either "2" on the keyboard; that might confuse them."