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Learning Objective

• To read and interpret Roman numerals from I to C (1 to 100) confidently, and understand how the numeral system evolved to include the concept of zero and place value.

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Success Criteria

• I can recognise and read Roman numerals up to 100 correctly.
• I can explain the rules for reading and writing Roman numerals.
• I can describe how the numeral system changed over time to include zero and place value.
• I can justify my answers using clear reasoning and evidence.

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Curriculum Links

(Ref: National Curriculum for England, Mathematics, Key Stage 2 - Year 4)

• Number – Number and Place Value:
  • Count in multiples of 6, 7, 9, 25, and 1000.
  • Recognise the place value of each digit in a four-digit number (thousands, hundreds, tens, and ones).
• Number – Addition and Subtraction:
  • Solve problems involving numbers up to 100 and beyond, including Roman numerals.
• History of Mathematics:
  • Understand that number systems, such as Roman numerals, have evolved.

Aligned with White Rose Maths - Place Value and Number Facts units.

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Resources Required

• Whiteboard and markers
• Individual whiteboards for students
• Printed charts of Roman numerals I to C
• Partially completed Roman numeral conversion sheet (for paired work)
• Timer

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Introduction (5 minutes)

Engage:
Display the numbers 1, 5, 10, 50, and 100 alongside their Roman equivalents (I, V, X, L, C) on the board. Ask:

• “Do you recognise these symbols?”
• “Who can tell me what these Roman numerals represent?”

Questioning to provoke curiosity:

• “Why do you think these numbers don’t look like the ones we usually write?”
• “How might ancient people have counted without zero or place value?”

Quick interactive starter:
Show random Roman numerals up to 100 and ask pupils to write down what they think the number is on their mini whiteboards.

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Main Teaching (15 minutes)

1. Modelling Reading Roman Numerals (7 minutes)

• Explain additive and subtractive notation clearly:
  • Example: III = 3 (1+1+1), IV = 4 (5-1), IX = 9 (10-1)
• Use a number line to map Roman numerals up to 100.
• Display partially worked example on the board for 67 = LXVII:
  • L = 50
  • X = 10
  • V = 5
  • I + I = 2
  • 50 + 10 + 5 + 2 = 67

AFL check:

• Ask pupils to hold up the Roman numeral for 20 and explain how they worked it out verbally. Use a timer for 30 seconds to encourage concise explanations.
• Use sentence stems:
  • “I know this is... because...”
  • “The symbol... means...”
  • “I added/subtracted ... because ...”

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2. Explaining Evolution of Number Systems (5 minutes)

• Brief explanation about the absence of zero and place value in Roman numerals.
• Introduce how the Hindu-Arabic numeral system changed counting – place value lets us represent bigger numbers simply and zero acts as a placeholder.

Questioning (Bloom’s Taxonomy):

• “Why do you think the Romans didn’t have a symbol for zero?” (Evaluation)
• “How would counting be more difficult without place value?” (Analysis)
• “Can you think of other examples where not having zero might cause confusion?” (Application)

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3. Paired Task - Complete Partially Worked Example (3 minutes)

• Pupils work in pairs to complete converting 84 (LXXXIV) using a partially filled table:

Symbol	Meaning	Number in Numerals
L	50
X	10
X	10
X	10
I	1
V	5

• Pupils calculate total and write how they worked it out step by step.

AFL prompt:

• Circulate and ask pairs to explain their reasoning using sentence stems. E.g., "We know this is 50 because..."

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Common Misconceptions and Areas of Difficulty

• Pupils often add all values without recognising subtractive notation (e.g., interpreting IV as VI = 6).
• Confusing similar symbols (e.g., V and X, or L and C).
• Not understanding zero’s role and the concept of place value evolution.
• Assuming Roman numerals can be written in any order or repeated more than three times consecutively.

Teaching tip: Emphasise the rules explicitly (no more than 3 repetitions of the same numeral, subtractive forms only in certain places).

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Layered Questioning (Whole-Class Discussion)

1. Remembering/Understanding:

   • “What does the Roman numeral X represent?”
   • “How is IV different from VI?”

2. Applying:

   • “Can you write the number 42 in Roman numerals? Explain your process.”

3. Analysing:

   • “Why can’t the numeral ‘IIII’ be used to represent 4? What rule forbids this?”

4. Evaluating:

   • “If Roman numerals were still used today, how might that affect our everyday life, especially in maths?”

5. Creating:

   • “Can you design a short code using Roman numerals and explain the rules someone else would need to decode it?”

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Task: Increasing Complexity (5 minutes)

• Start: Match numerals to their values (e.g., I = 1, V=5).
• Progress: Convert numbers from 1 to 20 from Roman to Arabic numerals and vice versa.
• Challenge: Convert larger numbers like 73, 89, or 100, combining additive and subtractive rules.
• Extension: Explain why zero cannot be expressed as a Roman numeral and how place value helps us write numbers beyond 100.

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Plenary (5 minutes)

• Quick oral quiz with timer (using mini whiteboards):
  • Show a Roman numeral; pupils write Arabic number (e.g., XLIII).
  • Show a number; pupils write the Roman numeral (e.g., 56).
• Ask pupils to verbally explain one thing they learned about Roman numerals and one thing about why place value and zero matter.
• End with a reflection question:
  • “How is the Roman numeral system different from the one we use now, and why is ours easier for calculations?”

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AFL Throughout the Lesson

• Use mini whiteboards for immediate feedback during questioning.
• Teacher circulates during paired work to check understanding and challenge thinking.
• Use timers during verbal explanation to encourage clear, concise reasoning.
• End of lesson exit ticket: Pupils write one example of a Roman numeral and how they know its value.

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Example for Pupil Book

Example: Convert LXIV to a number.

• L = 50
• X = 10
• IV = 4 (Because I before V means subtract 1)
• Add: 50 + 10 + 4 = 64

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Sentence stems to encourage reasoning:

• “I know this numeral represents... because…”
• “The smaller number before the bigger number means we... _____.”
• “I added/subtracted these values to make...”

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This lesson plan, following the National Curriculum and White Rose principles, engages pupils actively with Roman numerals and the historical context of number systems, encouraging deep thinking and reasoning skills.