6. The English method and Roman notation

The lesson, step by step

1. Warm-up

   Ask: What year is it in Roman numerals? Leave the answer open and come back to it.

2. The English method

   Read:

   In the English Method of Numeration six figures make a period.

   So in the old English way a billion meant a million millions. Today Americans and the British both use the French method that the book teaches first. Just notice the difference; no drill needed.

3. Roman letters

   Read:

   In the Roman Notation, numbers are represented by seven letters.

   I, V, X, L, C, D, M stand for 1, 5, 10, 50, 100, 500, 1000.

4. The principles

   Read each and try an example:

   Every time a letter is repeated, its value is repeated.

   Where a letter of less value is placed before one of greater value, the less is taken from the greater.

   Where a letter of less value is placed after one of greater value, the less is added to the greater.

   Where a letter of less value stands between two letters of greater value, it is taken from the following letter.

   A bar [—] placed over a letter increases its value a thousand times.

5. Guided practice

   Use the book's Roman Table. Cover the right side and have your student read XIV, XIX, XC, CM, MDCCCLXXX. Then cover the left side and write 49, 94, 444, 1880.

6. Independent practice

   Your student writes this year, their birth year and the year the book was published (about 1880) in Roman numerals.

7. Wrap-up

   Ask: Why is XIV fourteen and not sixteen? (The I stands between two larger letters, so it is taken from the V.)