Project Euler Forum

In the description of problem 89 there is a link to the explanation of Roman numerals. Since the server move, this link no longer works.

This is by far the easiest problem I'm failing on, so I keep having to read the descriptions to see if there is something I've overlooked.

jaap

Fixed.

Typo in the file http://projecteuler.net/index.php?secti ... n_numerals:

For example, in the famous Colesseum the the numerals above the forty-ninth entrance is written XXXXVIIII and not IL nor XLIX (see rules below).

The FAQ leaves out the most blatant exception to the "economy rule" that exists even to this day, which is that clock faces by tradition use IIII instead of IV. There is an endless debate about whether it is for aesthetic reasons or to avoid invoking Jupiter by carving the first two letters of his Latinized name, but there it is all the same.

Tirian wrote:The FAQ leaves out the most blatant exception to the "economy rule" that exists even to this day, which is that clock faces by tradition use IIII instead of IV. There is an endless debate about whether it is for aesthetic reasons or to avoid invoking Jupiter by carving the first two letters of his Latinized name, but there it is all the same.

I always thought that it was to make the ratio of the number of letters used of each type easier. With IIII you get 4 X's, 4 V's, 20 I's i.e. a 1:1:5 ratio. This is a lot easier to cope with than the 4:5:17 ratio it would otherwise be. This is of course only an advantage if the letters are manufactured separately and affixed to the clockface, rather than painted or engraved.