Roman notation is used on many clock faces, as well as for chapter numbers in the Bible and other books, for inscriptions on monuments, etc.

1. Review the following Roman numbers:

On clock faces 4 is often written IIII.

The letter X stands for 10. Placing X before each of the Roman numbers in Ex. 1 makes the Roman numbers from eleven through nineteen. Thus, XI = 11, XIV = · 14, XVI = 16, XIX = 19.

2. Read: XII, XIII, XI, XV, XVI, XVII, XIX, XVIII. 3. Write all the Roman numbers from 11 through 19. 4. Copy and memorize the following numbers:

Letters XX XXX XL L LX LXX LXXX XC Values 20 30 40 50 60 70

80

90

Placing each of the Roman numbers in Ex. 4 before the Roman numbers in Ex. 1 will make all the Roman numbers from twenty-one through ninety-nine. Thus, XXIV = 24, LVI = 56, XCIX = 99.

common experience. The business problems follow present business usage.

The pupil's self-activity is utilized in constructive work. His initiative is exercised by leading him to discover many arithmetical truths for himself. The importance of the correct interpretation of problems and of the choice of the best methods for their solution is emphasized. The "Problems Without Numbers" tend to develop the power of generaliza

tion.

This book for Middle Grades covers the work that is usually taught in the fifth and sixth years, each chapter representing one half year's work.

By the end of the sixth year, this book aims to give the pupils a knowledge of all the arithmetical principles that are essential for success in the ordinary affairs of life.

The effort to follow prevailing prices has been limited by their rapid fluctuations and by their variation in different parts of the country. Teachers should encourage pupils occasionally to substitute current local prices, thereby varying the problems in the book.

SAMUEL HAMILTON

Numbers play an important part in all the activities of life, and you cannot hope for much success unless you learn to handle them with ease.

Before you study the many new and interesting things about numbers that will be found in this book, it will be well to make sure that you have not forgotten what you have already learned. First of all, you must be able to read and write numbers rapidly and accurately. In your games and occupations, in your purchases at stores, and in your accounts of your earnings and expenditures, you do not often use very large numbers; but as you see them frequently in newspapers and magazines, you must learn to understand their meaning and to read them readily.

You have learned that the common method of reading and writing numbers makes use of the following ten figures: