See, they had to extend the A-F alphabet for hex in Canada because A is ambiguous and sounds like “eh?” if the A comes at the end.

For example, if I had decimal 42 as hexadecimal 2a, nobody would know if I meant “2a” or “2, eh?”.

So they needed a way to distinguish between them, and it was decided by the Looniputian and Toonipution council in 1981 to prefix any hexadecimal character A with R, because nobody would ever say “R eh?” in a real sentence.

Thus, decimal 42 in Canada would be 0x2ra and would be read as “2 R A, eh?”