Ray's New Practical Arithmetic · Art. 13 · Unit 1: Numeration
6. Roman numerals
Goal: Your child reads and writes Roman numerals using I, V, X, L, C, D and M.
You'll need
- The book
- A slate, small whiteboard or scrap paper
- A notebook and pencil
What's in the book
The Roman system of notation: seven letters and their values, numbers made by repeating letters, by putting a smaller letter before a larger one, and by putting it after. Then lists to write in Roman numerals.
The lesson, step by step
Warm-up
Ask if your child has seen Roman numerals: on a clock, a building, or a book's chapters.
The seven letters
Read:
To express numbers, the Roman Notation employs seven letters; namely, I, V, X, L, C, D, M.
I, one; V, five; X, ten; L, fifty; C, one hundred; D, five hundred; M, one thousand.
Write them on the slate with their values.
Before and after
Read:
Four numbers are expressed by a subtractive combination, as follows: IV, four; IX, nine; XL, forty; XC, ninety.
SayA smaller letter after a bigger one adds (VI is 6). A smaller letter before a bigger one subtracts (IV is 4).
Write together
Do the first list together:
The numbers from one to twenty,
Go slowly through IV, IX, XIV and XIX.
On their own
Your child writes the next lists: the numbers from twenty to thirty, and then 30, 40, 50 and so on to 90.
Wrap-up
Write the current year in Roman numerals together, one period at a time: thousands, hundreds, tens, units.
Answers to the book's problems
1 to 20: I, II, III, IV, V, VI, VII, VIII, IX, X, XI, XII, XIII, XIV, XV, XVI, XVII, XVIII, XIX, XX. 20 to 30: XX, XXI, XXII, XXIII, XXIV, XXV, XXVI, XXVII, XXVIII, XXIX, XXX. 30 to 90 by tens: XXX, XL, L, LX, LXX, LXXX, XC. For the later lists, build each number from thousands, hundreds, tens and units: for example 1877 is M + DCCC + LXX + VII = MDCCCLXXVII.
Worked out for this site from the scan. If a number in your copy differs, trust the book.