eighteen in one font

The eighteen in one font is a truncated version of the big GNU FreeFont (10 MB). The eighteen in one font named as "FreeSerifMath" contain the ASCII and the Mathematical Alphanumeric Symbols Unicode block. The Unicode block of the Mathematical Alphanumeric Symbols consists of Latin and Greek letters and decimal digits. There are a total of 18 different real character sets in the Mathematical Alphanumeric Symbols Unicode block.

The filled Unicode code blocks and empty code points
In the "FreeSerifMath.ttf" font the Unicode code blocks U+20 to U+7e (ASCII Unicode block) and U+1d400 to U+1d7ff (Mathematical Alphanumeric Symbols Unicode block) are filled. The Unicode code points U+1d6a6 and U+1d6a7 plus U+1d7cc and U+1d7cd are empty as original.

The Unicode codeblock Letterlike Symbols
In the original FreeFont are 24 Unicode code points empty in the "Mathematical Alphanumeric Symbols" Unicode code block, because these characters have in the original FreeFont references to the Unicode code block "Letterlike Symbols" from U+2100 to U+214F. The FreeSerifMath font was also truncaded to the Unicode code block "Letterlike Symbols" and the 24 empty code points have been filled with the reference characters from the "Letterlike Symbols" Unicode code block. You will find the 24 replaced characters listed in a table at the bottom.