all roman clocks still write number four as IIII instead of IV

The Roman numeral system, which originated in ancient Rome, is still used today for certain purposes such as numbering clock faces, books in a series, or designating rulers and popes. In the Roman system, numbers are represented by combinations of letters from the Latin alphabet: I (1), V (5), X (10), L (50), C (100), D (500), and M (1000).

Regarding the number four (IV), there's a common myth that it was written as IIII on ancient Roman clocks. However, this is not accurate. The Romans used IV consistently for the number four, not IIII. The reason behind this is rooted in the subtraction principle in Roman numerals:

• I stands for 1.
• V stands for 5.
• When you have a symbol of greater value before a lesser one, such as IV, you subtract the lesser value from the greater. Thus, V minus I equals 4.

Writing four as IIII would be equivalent to saying "one, one, one, one," which would simply add up to 4, similar to how you'd write it in Arabic numerals. It wouldn't follow the Roman subtraction principle.

In summary, both ancient and modern representations of Roman numerals correctly write the number four as IV, not IIII. This includes the use of Roman numerals on clock faces.