Since Version 5.1 there is a method available to enter any unicode character within the Math Editor using the Unicode codepoint toggle (as detailed by @ajlittoz in his answer). That method, as detailed below, works on both Linux & Windows.
I no longer use a Mac, so cannot comment on that, but the suggested method in the link is slightly different to ajlittoz’s method (I’ve tried both under Linux & both work):
To obtain any Unicode codepoint in the default font, Liberation Serif for
text, enter the code point and with cursor after the last character toggle
to display the glyph with <alt>+x. E.g. for U+00B0 DEGREE SIGN, enter
U+00B0 and then <alt>+x to toggle to °
You can also use the Symbols button and define a new entry in the Special
category for the degree sign, but I find the Unicode toggle to be more
I’m puzzled by ‘%angle’, and would like to know where it is documented. I assume that it is an Element, but can find zero mention of it’s use within the Help (f1). The glyph that it produces is also different to all other similar glyphs and
is NOT yet proves to be U+2222 SPHERICAL ANGLE. However, I cannot find which Unicode char it does come from.
U+2220 => ∠ (ANGLE)
U+2221 => ∡ (MEASURED ANGLE)
U+2222 => ∢ (SPHERICAL ANGLE)
U+2993 => ⦓ (LEFT ARC LESS-THAN BRACKET)
U+2996 => ⦖ (DOUBLE RIGHT ARC LESS-THAN BRACKET)
It is possible in Base since at least v3.4 to enter any unicode character using the UNICHAR(number) function. However, this is the Math Editor (full disclosure: I’ve never used it in anger) and that function cannot be used there.
The reason for the different appearance of ‘%angle’ cf U+2222 SPHERICAL ANGLE is that the latter uses the system font set via the menu whilst ‘%angle’ overrides the system font & force-uses OpenSymbol (those two glyphs differ a lot for this char) (I prefer the OpenSymbol glyph).
(tested using LO Version: 18.104.22.168 under Devuan Linux 2.1 (ascii))
If this helps then please tick the answer ()
…and/or show you like it with an uptick (∧)