# Year 4: Roman numerals

 Focused learning objectives Starter: Recognise the place value of each digit in a four-digit number (thousands, hundreds, tens and units/ones) Main: Read Roman numerals to 100 (I to C) and know that, over time, the numeral system changed to include the concept of zero and place value Success criteria Be familiar with the letters that the Romans used to represent numbers Understand the rules the Romans used to write numbers 1–100 Understand some of the differences between the number system we use today and the system the Romans used

Vocabulary

numeral, number, place value, place holder, digit, one-digit number, two-digit number, three-digit number, four-digit number

Resources

Starter
Individual whiteboards and pens for the children

Main
Large sheets of sugar paper split into a ten by two grid as shown in Figure 9.1 (these will combine in the plenary to make one big hundred square containing Roman numerals).

Ten by two grid

Plenary
A large 1–100 square (so children can compare and contrast Roman numerals with our number system)

Assessment opportunities

This lesson involves regular opportunities for children to discuss their thinking in pairs. Listen to the language they use and their confidence in justifying their reasoning.

Whilst they are working, ask children questions such as these:

• Why have you decided to write the number that way?
• How do you know you’ve recorded it correctly? What rules did you use?

#### Potential challenges

The numbers the children will find most challenging are those that involve the element of subtraction, e.g. 4, 9, 14, 19. Children may forget about this rule or apply the rule incorrectly; for example, they might record 19 as XVIIII or think they can record a number such as 8 as IIX (10 – 2). You might want to record a list of the ‘tricky’ numbers on the board to help remind the children of the numbers they can apply the subtraction rule to.

Look out for children who have a limited understanding of place value. Comparing and contrasting the Roman numerals to our number system may expose some gaps in understanding about how our number system works. Children may not have fully understood the significance of zero and how this is used as a place holder within our number system.

#### Ways the lesson could be adapted

For classes who find it challenging to work collaboratively the lesson could be structured so that children work in pairs to record as many numbers, using Roman numerals, as they can on a blank hundred square. They could then bring this to the plenary to compare and contrast it with our Hindu–Arabic hundred square.

For children who already have some prior knowledge of Roman numerals you could ask them to convert a number pattern into Roman numerals to explore whether similar patterns exist, e.g. 3, 13, 23, 33, 43, 53, etc. or 9, 18, 27, 36, 45, etc. This would again provide a good forum to compare and contrast the systems and to reinforce the importance of place value within the number system we use today.