History Biography Geography Science Games

Kids Math

Roman Numerals

• I = 1
• V = 5
• X = 10
• L = 50
• C = 100
• D = 500
• M = 1000

1. The first rule just says that you add letters, or numbers, if they come after a bigger letter or number. We demonstrated this in example 2 above. The V is less than the X, so we added it to the number. The I was less than the V, so we added it to the number. We'll discuss what happens when a letter of greater value comes after a letter of lesser value in rule 3.
2. The second rule is that you can't put more than three letters together in a row. For example, you can put three I's together, III, to make a 3, but you can't put four I's together, IIII, to make a four. How do you make a 4 then? See rule number three.
3. You can subtract a number by putting a letter of lower value before one of higher value.
This is how we make the numbers four, nine, and ninety:
• IV = 5 - 1 =4
• IX = 10 - 1 = 9
• XC = 100 - 10 = 90
There are a few restrictions on when you can do this:
• You can only subtract one number. You can't get a 3 by writing IIV.
• You can only do this with I, X, and C. Not with V, L, or D.
• The smaller (subtracted) letter must be either 1/5th or 1/10th the larger one. For example, 99 cannot be written IC because I is 1/100th of C.
4. The last rule is that you can put a bar over a number to multiply it by a thousand and make a really big number.

Back to Kids Math

Back to Kids Study

Search Ducksters

US History Native Americans Colonial America American Revolution Industrial Revolution American Civil War Westward Expansion The Great Depression Civil Rights Movement Pre-1900s 1900 to Present US Government US State History Homework Animals Math History Biography Money and Finance Biography Artists Civil Rights Leaders Entrepreneurs Explorers Inventors and Scientists Women Leaders World Leaders US Presidents Games Math Games Puzzle Games Word Games Geography Games Classic Games Sports Games Arcade Games Typing Games World History Ancient Africa Ancient China Ancient Egypt Ancient Greece Ancient Mesopotamia Ancient Rome Middle Ages Islamic Empire Renaissance Aztec, Maya, Inca French Revolution World War 1 World War 2 Cold War Art History Science Biology Chemistry Earth Science Physics Geography United States Africa Asia Central America Europe Middle East North America Oceania South America Southeast Asia Fun Stuff Arts and Crafts Holidays Jokes for Kids Movies Music Sports

About Ducksters Privacy Policy 

 

This site is a product of TSI (Technological Solutions, Inc.), Copyright 2024, All Rights Reserved. By using this site you agree to the Terms of Use.