Unicode in Ubuntu

Unicode, Ubuntu and diacritics

How to enter Unicode characters into OpenOffice.org under Ubuntu:

1. <Shift> <Ctrl> U
2. Enter the 4 digit / character Unicode code
3. Press <space> or <enter>

Initially an underlined capital U will appear: U
Then the number you entered: U13cd
Finally the character is displayed: Ꮝ

For reference, here is a page with tables of codes.

They are usefully tabulated:

Range  Decimal Name         Character
0x2014 8212    EM DASH          —
0x20A2 8354    CRUZEIRO SIGN    ₢
0x20AC 8364    EURO SIGN        €
0x2103 8451    DEGREE CELSIUS   ℃
0x2122 8482    TRADE MARK SIGN  ™ 
0x221A 8730    SQUARE ROOT      √
0x2713 10003   CHECK MARK       ✓
0x2714 10004   HEAVY CHECK MARK ✔
0x2717 10007   BALLOT X         ✗
0x2718 10008   HEAVY BALLOT X   ✘