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October 31st, 2015, 09:51 AM  #1 
Senior Member Joined: Nov 2010 From: Indonesia Posts: 2,001 Thanks: 132 Math Focus: Trigonometry  4 = iiii? Several days ago I read an encyclopedia about Weather and Season, and there was an image of a sundial using Roman numerals on it. On the sundial, the number 4 wasn;t written as IV, but IIII. Initially I thought that the writing system of Roman numerals in its early age didn't allow us to substract with the left numbers. Strangely, when I read in the place of the number 9, it was still written as IX and not VIIII. How could it be like this? 
October 31st, 2015, 09:58 AM  #2 
Math Team Joined: Dec 2013 From: Colombia Posts: 7,675 Thanks: 2655 Math Focus: Mainly analysis and algebra 
In Renaissance France, King Louis XIV(?) preferred the more balanced look of clocks showing IIII instead of IV. The look quickly became standard.

November 1st, 2015, 07:35 AM  #3 
Math Team Joined: Jul 2011 From: Texas Posts: 3,003 Thanks: 1588  
November 1st, 2015, 12:06 PM  #4 
Global Moderator Joined: Nov 2006 From: UTC 5 Posts: 16,046 Thanks: 938 Math Focus: Number theory, computational mathematics, combinatorics, FOM, symbolic logic, TCS, algorithms 
As previously alluded to, the Romans didn't use subtractive notation, that was a medieval innovation. Further, the rule that whenever you can subtract you should (though only one 'step' down) is even more modern. So the preference of clockmakers  for which I've heard the same explanation, that the appearance is more balanced  is not surprising to me.

November 1st, 2015, 06:52 PM  #5 
Senior Member Joined: Nov 2010 From: Indonesia Posts: 2,001 Thanks: 132 Math Focus: Trigonometry 
But... weren't sundials invented way before clocks?

November 1st, 2015, 07:17 PM  #6 
Math Team Joined: Dec 2013 From: Colombia Posts: 7,675 Thanks: 2655 Math Focus: Mainly analysis and algebra 
Invented, yes. But they were made since the invention of the clock too. And the aesthetic argument would hold for both.

November 10th, 2015, 09:20 AM  #7 
Member Joined: Jun 2015 From: Ohio Posts: 99 Thanks: 19 
This is very helpful. I always thought the person who made the clock in my living room made a mistake. Lol

November 11th, 2015, 10:19 PM  #8 
Newbie Joined: Nov 2015 From: Texas Posts: 4 Thanks: 0 Math Focus: Algebra 
Kings are rulemakers... it's good to rule and make new rules.
Last edited by skipjack; November 12th, 2015 at 02:10 AM. 