Lesson 2: Roman Numerals

Rules of Roman Numerals:

Roman numerals are represented by letters from the Latin alphabet
Each letter has a corresponding value
When a smaller value appears before a larger value, you subtract the smaller value from the larger one
When a smaller value appears after a larger value, you add the smaller value to the larger one.
The same letter can't appear more than three times in a row.
Larger numbers are formed by combining these symbols and rules

Roman Numerals

I = 1

V = 5

X = 10

L = 50

C = 100

D = 500

Lesson Quiz:

Take the Lesson Quiz below. The answers are also provided underneath if you’d like to see which ones you got wrong.

1. What is the decimal number for the Roman numeral XXV?
  ✅ A. 25
2. What is the Roman numeral for the decimal number 76?
  ✅ A. LXXVI
3. What is the decimal number for the Roman numeral DCLXVI?
  ✅ D. 666
4. What is the Roman numeral for the decimal number 500?
  ✅ B. D
5. What is the decimal number for the Roman numeral CXLIV?
  ✅ A. 144
6. What is the Roman numeral for the decimal number 399?
  ✅ A. CCCXCIX
7. What is the decimal number for the Roman numeral CD?
  ✅ A. 400
8. What is the Roman numeral for the decimal number 888?
  ✅ C. DCCCLXXXVIII
9. What is the decimal number for the Roman numeral CM?
  ✅ C. 900
10. What is the Roman numeral for the decimal number 789?
  ✅ A. DCCLXXXIX