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Roman numerals

You learn to read Roman numerals and change them to ordinary numbers.

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How to work it out

  1. I is 1, V is 5, X is 10, L is 50, C is 100, D is 500 and M is 1000.
  2. Add up the values.
  3. If a smaller numeral is before a larger one (like IV or IX), take it away.
D1.000
1
H100
0
T10
5
E1
4
1000 + 50 + 4=1054

A worked example

XVI

  1. Look at the letters: X is 10, V is 5 and I is 1.
  2. The letters go from biggest to smallest.
  3. Add the values: 10 + 5 + 1 = 16.
  4. The number XVI is 16.
More examples

XIV

  1. X is 10 and IV is 5 − 1 = 4.
  2. Add together: 10 + 4 = 14.
  3. The number is 14.

XLV

  1. XL is 50 − 10 = 40 and V is 5.
  2. Add together: 40 + 5 = 45.
  3. The number is 45.

Try it yourself

  1. Convert the Roman numeral to an ordinary number

    What number is the Roman numeral LIV?

  2. Convert the Roman numeral to an ordinary number

    What number is the Roman numeral XL?

Watch out

  • You forget to take away when a smaller numeral comes before a bigger one, like IV.

    Is a smaller numeral before a bigger one? Then take the small value away from the big one.

Tips

  • I=1, V=5, X=10, L=50, C=100, D=500 and M=1000.
  • If a smaller symbol comes before a bigger one, take it away (like IV = 4 and IX = 9).

Why it works

The Romans used letters for numbers: I, V, X, L, C, D and M. You add the letters together, unless a smaller letter stands in front of a bigger one: then you take it away.