P6 Mathematics - Term I

Topic 2: Whole Numbers

Lesson 4: Introduction to Roman Numerals

Duration: 45 minutes

Learning Objectives

By the end of this lesson, you will be able to:

• Identify the seven Roman numeral symbols
• State the value of each symbol
• Apply addition and subtraction rules
• Convert between Roman and Hindu-Arabic numerals

Have You Seen These?

I, II, III, IV, V...

Where have you seen numbers like this?

• Clock faces
• Movie titles (Rocky IV)
• Chapter numbers
• Building dates

Roman Numerals

Numbers used by ancient Romans over 2,000 years ago!

They use LETTERS instead of digits.

And we still use them today!

The Seven Symbols

These are the building blocks of ALL Roman numerals!

Learn the Seven Symbols

Memory Trick!

I Value Xylophones Like Cows Do Milk

I = 1
V = 5
X = 10
L = 50
C = 100
D = 500
M = 1,000

Important Rules!

1. Always write in CAPITAL LETTERS

   • ✓ IV, X, M
   • ✗ iv, x, m

2. There is NO ZERO in Roman numerals!

The Addition Rule

When a smaller value comes AFTER a larger value:

ADD them together!

Addition Examples

You Can Repeat Symbols

Repeat I, X, C, or M up to three times:

The Subtraction Rule

When a smaller value comes BEFORE a larger value:

SUBTRACT the smaller from the larger!

Subtraction Examples

Position Matters!

IV ≠ VI

• IV = 5 - 1 = 4 (subtract)
• VI = 5 + 1 = 6 (add)

The position of the smaller number changes everything!

Rules for Subtraction

Only I, X, and C can be used for subtraction:

Never Do These!

VX (use V only, not for subtraction)
LC (L cannot be used for subtraction)
IIII (use IV for 4)
VV (never repeat V, L, or D)
XXXX (maximum three X's)

Numbers 1-10

Your Turn!

What is the value of each Roman numeral?

1. VII = ?
2. XII = ?
3. XIV = ?
4. XIX = ?

Answers

1. VII = 5 + 1 + 1 = 7
2. XII = 10 + 1 + 1 = 12
3. XIV = 10 + (5 - 1) = 10 + 4 = 14
4. XIX = 10 + (10 - 1) = 10 + 9 = 19

Your Turn!

Write these in Roman numerals:

1. 3 = ?
2. 8 = ?
3. 15 = ?
4. 40 = ?

Answers

1. 3 = III (1 + 1 + 1)
2. 8 = VIII (5 + 1 + 1 + 1)
3. 15 = XV (10 + 5)
4. 40 = XL (50 - 10)

Larger Numbers

Quick Quiz

Question 1:
What is the Roman numeral for 100?

Answer 1

The Roman numeral for 100 is:

C

(Think: Century = 100 years!)

Quick Quiz

Question 2:
What is the value of LX?

Answer 2

LX = 50 + 10 = 60

(L = 50, X = 10, smaller after larger = ADD)

Quick Quiz

Question 3:
What is the value of XC?

Answer 3

XC = 100 - 10 = 90

(X = 10, C = 100, smaller before larger = SUBTRACT)

Summary: The Seven Symbols

Addition: Smaller AFTER larger → ADD
Subtraction: Smaller BEFORE larger → SUBTRACT

Key Points to Remember

1. Seven symbols: I, V, X, L, C, D, M
2. Always CAPITALS
3. No zero in Roman numerals
4. Position matters: IV ≠ VI
5. Only I, X, C can subtract
6. Maximum three of the same symbol

Homework

1. Write all seven symbols and their values

2. Convert to numbers:

   • VIII, XIII, XL, LXX, XC

3. Convert to Roman numerals:

   • 3, 9, 15, 40, 90

4. Find one real-life example of Roman numerals

Time: 20-25 minutes

Next Lesson Preview

Tomorrow: Roman Numerals in Real Life!

We will practice reading:

• Clock faces
• Dates on buildings
• Years (like 2025 = MMXXV)
• And more!

Great Work Today!

You learned:

• The seven Roman numeral symbols
• Their values (1, 5, 10, 50, 100, 500, 1000)
• Addition rule (smaller after = add)
• Subtraction rule (smaller before = subtract)

I, V, X, L, C, D, M - You've got this!

Credits

Created: November 30, 2025
Based on: NCDC P6 Mathematics Curriculum - Topic 2: Whole Numbers

Source: National Curriculum Development Centre (NCDC), Uganda

Available from: https://ncdc.go.ug/