Here is a basic explanation for reading/writing Roman numerals from 1 to 100:
- "I" is 1
- "V" is 5
- "X" is 10
- "L" is 50
- "C" is 100
Each letter is a number that either begins with a 1 or a 5. There is no letter representing 0 in Roman numerals. Also, any numbers that end with 4 or nine ALWAYS end with “IV” or “IX.” There are NEVER more than three of the same letter written consecutively. Thus, 8 is VIII and 9 is IX. The logic of this is as follows.
- 7 is two places after 5, so you write VII. (two after 5)
- 9 is four places after 5, but your can’t have more than three of the same letter written consecutively, so you say 9 is one place before 10, so you write IX. (one before 10) This is the same with 4, you can’t have four I’s in a row, so you say it is one before 5, or IV.
- When you get the teens, twenties, and beyond, you start back at 1, but you place the appropriate number of X’s at the beginning, so 14 is XIV, 26 is XXVI, 29 is XXIX, and so on.
So here are the 39 numerals: I, II, III, IV, V, VI, VII, VIII, IX, X, XI, XII, XIII, XIV, XV, XVI, XVII, XVIII, XIX, XX, XXI, XXII, XXIII, XXIV, XXV, XXVI, XXVII, XXVIII, XXIX, XXX, XXXI, XXXII, XXXIII, XXXIV, XXXV, XXXVI, XXXVII, XXXVIII, XXXIX.
Wait! Didn’t you say that you can have more than three of the same letter in a single numeral?
No, I said you can’ have more than three of the same letter written CONSECUTIVELY. 39 (XXXIX) is perfectly fine.
Now here’s where things get interesting.
Since you’re not allowed to have more than three of the same letter written consecutively, we run into problem when trying to write the number 40. However since “L” is 50, we simply put an “X” before it, which says it is ten less than 50. 40 is written “XL.” Then you continue counting until you reach 50, or “L.”
XLI, XLII, XLIII, XLIV, XLV, XLVI, XLVII, XLVIII, XLIX, L.
When you reach 60 you put an “X” after the “L,” because 60 is ten more than 50. Let’s keep counting until we reach 89:
LI, LII, LIII, LIV, LV, LVI, LVII, LVIII, LIX, LX, LXI, LXII, LXIII, LXIV, LXV, LXVI, LXVII, LXVIII, LXIX, LXX, LXXI, LXXII, LXXIII, LXXIV, LXXV, LXXVI, LXXVII, LXXVIII, LXXIX, LXXX, LXXXI, LXXXII, LXXXIII, LXXXIV, LXXXV, LXXXVI, LXXXVII, LXXXVIII, LXXXIX.
Here’s where things get complicated. I said that you can’t have more than three of the same letter written consecutively. This doesn’t apply to 5, 50, and so on. V’s and L’s can only be written once for each numeral. You don’t have LL for 100 or VV for 10. This means that when you write the number 90, you have to use XC, because 90 is ten less than 100. I’m now going to write the next 11 numerals from 90 to 100:
XC, XCI, XCII, XCIII, XCIV, XCV, XCVI, XCVII, XCVIII, XCIX, C.
So there you go, you now have all the numerals from 1 to 100. Now just continue the pattern until you reach 1000. In order to do so, however, you’ll need two more letters for 500 and 1000.
This post was written on II/VIII/MMXIV