What is the Difference between Additive notation and Subtractive notation in Roman numerals?
correct me if im wrong but this is an example of Additive: XXXIII = 10 + 10 + 10 + 1 + 1 + 1 = 33
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$\begingroup$ Yes, that’s an example of additive notation. IX $=10-1=9$ is an example of subtractive notation, as is XC $=100-10=90$. Roman numerals were originally entirely additive; the subtractive notation was a later development. $\endgroup$– Brian M. ScottCommented May 23, 2012 at 6:51
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$\begingroup$ Thanks for that you made it really clear :) $\endgroup$– Daniel Del CoreCommented May 23, 2012 at 6:52
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$\begingroup$ @BrianM.Scott what would you say is the subtractive notation of my example though? $\endgroup$– Daniel Del CoreCommented May 23, 2012 at 6:56
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1$\begingroup$ There isn’t one: the subtractive notation is used only when an amount written with a single letter is being subtracted. One doesn’t write IIV, meaning $5-2$, for $3$, and similarly, one doesn’t write XXXIIV, XXLIII, or XXLIIV, meaning $30+5-2,50-20+3$, and $50-20+5-2$, for $33$. $\endgroup$– Brian M. ScottCommented May 23, 2012 at 7:00
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1$\begingroup$ Just as an example for subtractive notation, 1999 is not generally written "IM", as might be supposed, but rather "MCMXCIX". $\endgroup$– JL344Commented Jul 2, 2012 at 6:13
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IIII and IV are both used for 4. IIII is additive; IV is subtractive.
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$\begingroup$ Actually four repetitions of the same symbol became common during the Middle Ages. During the golden age of the Roman civilization (I century BC) only up to three repetitions were allowed by "proper grammar", so to speak. $\endgroup$– AndyCommented Jul 2, 2012 at 8:15
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$\begingroup$ @Andy This seems to be the opposite of what Wikipedia claims: en.wikipedia.org/wiki/Subtractive_notation $\endgroup$– domotorpCommented Dec 26, 2017 at 19:53