# Roman numerals Subtractive VS Additive

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

• 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. Commented May 23, 2012 at 6:51
• Thanks for that you made it really clear :) Commented May 23, 2012 at 6:52
• @BrianM.Scott what would you say is the subtractive notation of my example though? Commented May 23, 2012 at 6:56
• 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 $33$. Commented May 23, 2012 at 7:00
• Just as an example for subtractive notation, 1999 is not generally written "IM", as might be supposed, but rather "MCMXCIX". Commented Jul 2, 2012 at 6:13