Roman Numerals, and a Classic Error

When a number appears in a cryptic clue, a possible interpretation is that its Roman numeral has to be substituted to get the answer.

Examples:

Times 24440: Insects: bumping fifty off takes such an age (3) ICE
                     LICE (insects) – L (Roman numeral for 50)

FT 13332 (Sleuth): Surpass 40 in Rome, we hear? (5) EXCEL
                            Homophone of XL (Roman numeral for 40)

The number may be well-disguised, as in:

Times 23960: Businessman returning about half of score composed (7) RELAXED
                     DEALER (businessman) reversed, around X (Roman numeral for 10, which is half of score i.e. 20)

Roman Numerals: Quick Reference Table

Setters have more use for a number like 100 (Roman numeral: C) than 123 (Roman numeral: CXXIII).

A quick reference table for the numbers you are most likely to encounter in clues:

Number Roman Numeral 1 I 2 II 3 III 4 IV 5 V 6 VI 7 VII 8 VIII 9 IX 10 X 11 XI 40 XL 50 L Number Roman Numeral 51 LI 55 LV 60 LX 90 XC 100 C 101 CI 200 CC 400 CD 500 D 600 DC 1000 M 1001 MI 2000 MM

Spot The Error

We may come across published clues like the next three, but there is something wrong with them. Do you see the error?

NIE 13-Aug-09: Fifty is under forty-nine? Well, no (3) ILL

THC 9454 (Sankalak): One making an earnest appeal to displace about 99 (10) SUPPLICANT

Guardian 24643 (Gordius): It melts for about 99 bucks (2-4) DE-ICER

Update (08-Jun-2010): Congrats to GreenMangoMore, Anon, maddy, gnomethang, Balaji, veer, Sanjeev (on twitter), raju for getting it right. For those still in the dark, the explanation:

The Classic Roman Numeral Mistake

On the face of it, IL and IC appear to follow the same subtractive principle as IV and IX, i.e. IL = L (50) - I (1) = 49.

This is actually not valid.

The subtractive principle for Roman numbers has these restrictions:
You can only subtract a power of ten, and only from the next two higher "digits", where the digits are {I, V, X, L, C, D, M}.

That is, only I, X and C can be subtracted, AND
I can be subtracted only from V and X; X can be subtracted only from L and C; C can be subtracted only from D and M.

By these rules, the Roman numerals IL for 49 and IC for 99 do not work.
The correct representation for 49 is XLIX, for 99 is XCIX.

Veer mentions "cryptic licence". Given that we see so much of IC and IL even in the careful setters' clues, that is perhaps the sensible-liberal way to look at it - but to me it still seems wrong!

Related Posts:

• NATO Phonetic Alphabet in Crosswords
• Rhyming Slang
• Elementary Deceptions
• What’s wrong with this clue?

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