Grade 3: Roman Numerals

Warm up with a few quick roman numerals warm-ups on the board while the class settles, so every child starts thinking about the skill.

Roman numerals write numbers with seven letters, I, V, X, L, C, D and M. The rule is simple: symbols are written largest to smallest and added, unless a smaller symbol sits just before a bigger one, in which case it is subtracted. Students meet Roman numerals on clock faces, book chapters, monarch names and dates. Model the method clearly, thinking aloud:

• Start with the seven symbols and their values: I=1, V=5, X=10, L=50, C=100, D=500, M=1000.
• Teach the addition rule first, symbols written largest to smallest are added (VIII = 5 + 1 + 1 + 1 = 8).
• Then the six subtractive pairs (IV=4, IX=9, XL=40, XC=90, CD=400, CM=900), a smaller symbol before a larger one is subtracted.
• Practise both directions, number to numeral and numeral to number, and read a real analog clock face together.

Do the first few questions of the practice worksheet together, one child explaining each step. Check for understanding before releasing the class to work alone.

Students complete the worksheet independently. Hand out the three difficulty levels below so every child works at the right stretch.

Circulate and look for these, they are the usual sticking points:

• Writing a symbol four times in a row (IIII for 4 instead of IV).
• Subtracting the wrong symbol, only I, X and C are ever used to subtract.
• Reading IX as 11 instead of 9, the order decides add or subtract.
• Forgetting there is no zero in Roman numerals.

Pull the class back together. Ask one child to explain roman numerals in their own words, pose a single check question everyone answers on a mini whiteboard, and name what you will build on next lesson.

Use the independent worksheet as the evidence. A child who can complete it accurately and explain one answer has met the objective; anyone who cannot needs the easier level and a short reteach next session.