ROMAN NUMERAL RESOURCES
1. Roman numeral mathematics (there is a neat little converter built into this site, plus other information about using the numerals):
https://www.britannica.com/topic/Roman-numeral
2. Roman numerals in 3 simple rules: https://blog.innovamat.com/en/roman-numerals-in-3-simple-rules/
Some info from this site:
Seven symbols...
Roman numerals are made up of seven symbols that match up to seven uppercase letters of the Latin alphabet (I = 1, V = 5, X = 10, L = 50, C = 100 , D = 500, M = 1,000)
Using the seven previous symbols, you can represent any roman number, keeping in mind that the Romans didn’t consider 0, negatives or decimals. In Roman numerals, the symbols don’t change value but they are added or subtracted following certain rules. Let’s have a look at them:
Three rules...
Add
When a symbol is placed after (to the right of) a larger value, it is added. For example: XI = 10 + 1 = 11
Subtract
When a symbol is placed before (to the left of) a larger value, it is subtracted. For example: XL = 50 − 10 = 40 This way, when a symbol is between two larger numbers, it is subtracted from the symbol on the right. For example: XIX = 10 + (10 − 1) = 19.
Large numbers
Any number can be multiplied by 1 000 by drawing a horizontal line above it.
And three exceptions!
Don’t repeat a symbol more than 3 times in a row
There can’t be more than 3 of the same symbol in a row. For example, 4 can’t be written as IIII (IV).
Don’t repeat symbols that start with 5
The symbols V, L and D (5, 50 and 500, respectively) cannot be repeated.
Not all symbols can be subtracted
Be careful because this is the exception that gives our student most difficulty! Only the symbols I, X and C (1, 10 and 100 respectively) can subtract and can only subtract the 2 symbols that are immediately larger. So, I can only subtract V or X, X can only subtract L or C, and C can only subtract M. That is, there are only 6 possible subtraction combinations: IV = 5 − 1 = 4; IX = 10 − 1 = 9; XL = 50 − 10 = 40; XC = 100 − 10 = 90; CD = 500 − 100 = 400; y CM = 1000 − 100 = 900.
Some of these rules have changed throughout history. For example, it isn’t hard to find ancient texts in which 4 is written as IIII instead of IV.
However, with these rules and exceptions in mind, today we can write Roman numerals correctly.
3. Calculator Soup (here is another Roman Numeral converter):
https://www.calculatorsoup.com/calculators/conversions/roman-numeral-converter.php
Some info from this site:
The largest number you can write in Roman numerals is 3,999 which is MMMCMXCIX. You can represent numbers larger than 3,999 in Roman numerals using an overline. An overline on a Roman numeral means you are multiplying that Roman numeral by 1,000. For the number 50,000 in Roman numerals you would use the Roman numeral L (50) with an overline to make it 50,000.
For example, L means 50 × 1,000 = 50,000.
4. Roman Numerals (There are some handy downloadable charts here):
