Hexadecimal
Distinguishing from decimal

In contexts where the base is not clear, hexadecimal numbers can be ambiguous and confused with numbers expressed in other bases. There are several conventions for expressing values unambiguously. A numerical subscript (itself written in decimal) can give the base explicitly: 159 is decimal 159; 159 is hexadecimal 159, which equals 345. Some authors prefer a text subscript, such as 159 and 159, or 159 and 159.

Donald Knuth introduced the use of a particular typeface to represent a particular radix in his book The TeXbook. Hexadecimal representations are written there in a typewriter typeface: 5A3, C1F27ED

In linear text systems, such as those used in most computer programming environments, a variety of methods have arisen:
detectable_content:number_placeholders[8], length_constraints:number_sentences[5], oulipo:avoid_letter[t]