Hex Hexadecimal Notation ───────────────────────────────────────────────── A base-16 numbering system, used by programmers. It uses the 16 digits: 1 2 3 4 5 6 7 8 9 a b c d ───────────────────────────────────────────────── ■ TECH Help! shows hex numbers suffixed with "H". ■ Assemblers and Debug require hex numbers beginning with "a-f" to start with a leading 0. TECH Help! does not follow this convention.