CHAPTER V
HOW ROBERT AND WU AND CAIUS ADDED NUMBERS
" I don't see how they ever added numbers when they wrote them as the Romans did , ' said Irene , just to get the Story - Teller started . The numerals that Hippias used were worse," said Edward . But Daniel's were still worse , " said Will .
" Ahmes and Lugal had the worst of all, " added Dorothy.
" I see," said the wise old Story- Teller, "that the Crowd has planned all this talk just to get me started " ; at which the Tease smiled significantly.
" Well , it is true that they all had trouble with their numerals," he continued , " and tonight I am going to tell you a story about 45
NUMBER STORIES
some of the troubles of three boys who found ways of adding numbers in spite of their awkward numerals ."
When Caius was a boy he attended a kind of business school. There he learned how to write, to read the parchment rolls that told of business customs , and to perform the only two operations with numbers that were then considered absolutely necessary. These operations were addition and subtraction , and when we come to think of it they cover a large part of our business arithmetic to - day. It is not often that we need a long multiplication or a long division .
If you are asked to add 257 and 369 you find the work so easy that you can hardly imagine that it would ever trouble anyone . But when his teacher told Caius to add these numbers written in the Roman numerals , the problem did not seem so simple. It is really easier, however , than one would at first think, and if arithmetic required only adding, the Roman numerals would not be very difficult. In the first place the Romans usually wrote IIII instead of IV , VIIII instead of IX , and
so on, and if you do this you will find it about as easy to add with Roman numerals as with our own .
After learning to add , which he found quite easy, Caius learned to subtract, and that was also easy ; but when he came to multiplying or dividing with Roman numerals he at once found himself in a great deal of trouble.
HOW CAIUS ADDED 257 AND 369
Caius had six I's , so he wrote VI below ; he had two V's , so he wrote X below ; he had one X , so he wrote X below that ; he had two L's , so he wrote C below ; and he had five other C's , so he wrote D below them
Although Caius learned how to add and subtract with Roman numerals, there was another method that was more common . He learned that pebbles were used in working with numbers . He found that he could draw lines on a board, - one to represent units , another to represent tens, and so on , and that he could then place pebbles on these lines.