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Roman Numerals

Seven letters. Two rules. A whole number system. Everything a classical homeschool student needs to read Roman numerals fluently — from a clock face to a chapter heading to an ancient inscription.

The 7 Letters

Roman numerals are built from just seven capital letters. Memorize these and you can read any Roman numeral.

one

five

ten

fifty

100

one hundred (centum)

500

five hundred

1,000

one thousand (mille)

The Two Rules

Rule 1: Addition

When a letter is followed by a letter of equal or smaller value, you add them together.

VI = V + I = 5 + 1 = 6
LX = L + X = 50 + 10 = 60
MMXX = M + M + X + X = 1000 + 1000 + 10 + 10 = 2020
LXXVIII = L + X + X + V + I + I + I = 78

Rule 2: Subtraction

When a letter is followed by a letter of larger value, you subtract the smaller from the larger.

IV = V − I = 5 − 1 = 4
IX = X − I = 10 − 1 = 9
XL = L − X = 50 − 10 = 40
CM = M − C = 1000 − 100 = 900

Only these 6 subtraction pairs are allowed: IV, IX, XL, XC, CD, CM. You cannot write 99 as IC — it has to be XCIX.

1 to 20

III

VII

VIII

XII

XIII

XIV

XVI

XVII

XVIII

XIX

10 to 100 (by tens)

XXX

LXX

LXXX

100

100 to 1000 (by hundreds)

100

200

300

CCC

400

500

600

700

DCC

800

DCCC

900

1000

How to Read Any Roman Numeral

For numbers larger than 20 or 100, the trick is to read the numeral from left to right in chunks — thousands, then hundreds, then tens, then ones.

Example: MCMXCIV

M = 1000 (thousands chunk)
CM= 900 (subtraction pair: 1000 − 100)
XC= 90 (subtraction pair: 100 − 10)
IV= 4 (subtraction pair: 5 − 1)
Total: 1000 + 900 + 90 + 4 = 1994

The key insight: when you see two letters where the left one is smaller, treat them as a pair, not as separate additions. Read pairs first, then chunks.

Roman Numerals in History

Classical homeschool students run into Roman numerals in date columns, chapter headings, book numbers, and real historical inscriptions. Here are the famous ones worth recognizing at a glance:

Year	Roman Numeral	Event
753	DCCLIII	Founding of Rome (traditional)
44	XLIV	Julius Caesar assassinated (44 BC)
476	CDLXXVI	Fall of the Western Roman Empire
800	DCCC	Charlemagne crowned Emperor
1066	MLXVI	Battle of Hastings
1492	MCDXCII	Columbus reaches the Americas
1776	MDCCLXXVI	US Declaration of Independence
1969	MCMLXIX	First moon landing
2026	MMXXVI	Current year

Common Gotchas

Only 6 subtraction pairs are legal. IV, IX, XL, XC, CD, CM. Anything else (like IL for 49 or VX for 5) is wrong. Students sometimes try to write 49 as IL; the correct form is XLIX.
No more than three of the same letter in a row. III and XXX are fine; IIII is not (that's why 4 is written as IV, not IIII, on everything except some antique clock faces that keep IIII for visual symmetry).
There is no zero. The Romans had no symbol for zero. For astronomical or calendar purposes they used the Latin word nulla(“nothing”), but it wasn't part of the numeral system.
V and X only subtract from the next value up.V never precedes another V, L, C, D, or M. X only subtracts from L or C. I only subtracts from V or X. Think of it as “one step at a time.”
Roman numerals are case-insensitive but convention is capitals. Lowercase (i, v, x) appears in old manuscripts and outlines. For modern use, stick with capitals.

Practice Latin with Via Latina

Roman numerals are part of the broader Latin curriculum. Via Latina has 500+ Latin vocabulary words, grammar drills, and games built for classical homeschool families. Free to start.

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The Two Rules

Rule 1: Addition

When a letter is followed by a letter of equal or smaller value, you add them together.

VI = V + I = 5 + 1 = 6
LX = L + X = 50 + 10 = 60
MMXX = M + M + X + X = 1000 + 1000 + 10 + 10 = 2020
LXXVIII = L + X + X + V + I + I + I = 78

Rule 2: Subtraction

When a letter is followed by a letter of larger value, you subtract the smaller from the larger.

IV = V − I = 5 − 1 = 4
IX = X − I = 10 − 1 = 9
XL = L − X = 50 − 10 = 40
CM = M − C = 1000 − 100 = 900

Only these 6 subtraction pairs are allowed: IV, IX, XL, XC, CD, CM. You cannot write 99 as IC — it has to be XCIX.

How to Read Any Roman Numeral

For numbers larger than 20 or 100, the trick is to read the numeral from left to right in chunks — thousands, then hundreds, then tens, then ones.

Example: MCMXCIV

M = 1000 (thousands chunk)
CM= 900 (subtraction pair: 1000 − 100)
XC= 90 (subtraction pair: 100 − 10)
IV= 4 (subtraction pair: 5 − 1)
Total: 1000 + 900 + 90 + 4 = 1994

The key insight: when you see two letters where the left one is smaller, treat them as a pair, not as separate additions. Read pairs first, then chunks.

Roman Numerals in History

Classical homeschool students run into Roman numerals in date columns, chapter headings, book numbers, and real historical inscriptions. Here are the famous ones worth recognizing at a glance:

Year	Roman Numeral	Event
753	DCCLIII	Founding of Rome (traditional)
44	XLIV	Julius Caesar assassinated (44 BC)
476	CDLXXVI	Fall of the Western Roman Empire
800	DCCC	Charlemagne crowned Emperor
1066	MLXVI	Battle of Hastings
1492	MCDXCII	Columbus reaches the Americas
1776	MDCCLXXVI	US Declaration of Independence
1969	MCMLXIX	First moon landing
2026	MMXXVI	Current year

Common Gotchas

Only 6 subtraction pairs are legal. IV, IX, XL, XC, CD, CM. Anything else (like IL for 49 or VX for 5) is wrong. Students sometimes try to write 49 as IL; the correct form is XLIX.

No more than three of the same letter in a row. III and XXX are fine; IIII is not (that's why 4 is written as IV, not IIII, on everything except some antique clock faces that keep IIII for visual symmetry).

There is no zero. The Romans had no symbol for zero. For astronomical or calendar purposes they used the Latin word nulla(“nothing”), but it wasn't part of the numeral system.

V and X only subtract from the next value up.V never precedes another V, L, C, D, or M. X only subtracts from L or C. I only subtracts from V or X. Think of it as “one step at a time.”

Roman numerals are case-insensitive but convention is capitals. Lowercase (i, v, x) appears in old manuscripts and outlines. For modern use, stick with capitals.

The 7 Letters

The Two Rules

Rule 1: Addition

Rule 2: Subtraction

1 to 20

10 to 100 (by tens)

100 to 1000 (by hundreds)

How to Read Any Roman Numeral

Roman Numerals in History

Common Gotchas

Practice Latin with Via Latina

More classical references

Classical Education Curriculum Guide: The Trivium Explained for Parents

The Best Way to Learn Latin for Beginners (Classical Education Edition)

Teaching Latin to Kids: Why CC Families Start with Noun Declensions

The 7 Letters

The Two Rules

Rule 1: Addition

Rule 2: Subtraction

1 to 20

10 to 100 (by tens)

100 to 1000 (by hundreds)

How to Read Any Roman Numeral

Roman Numerals in History

Common Gotchas

Practice Latin with Via Latina

More classical references

Classical Education Curriculum Guide: The Trivium Explained for Parents

The Best Way to Learn Latin for Beginners (Classical Education Edition)

Teaching Latin to Kids: Why CC Families Start with Noun Declensions