Page:Smith - Number Stories of Long ago (1919).djvu/88

OF LONG AGO. schoolmaster could multiply much faster than any of them. He used the numerals that had come from the East, and so Leonardo was anxious to learn the new way.

If you have never seen a modern calculating machine, you would be interested to see how it works. You would watch the setting down of the multiplicand on certain keys, then you would see the multiplier set down, and then, on one of these modern machines, you would simply touch an electric button and the machine would make a little buzzing sound, after which you would read the answer upon it.

Some such curiosity and interest must have been Leonardo’s when he first saw his old Moorish schoolmaster multiply one number of three figures by another number of three figures. With the counters this would have taken him several minutes, but his teacher did it in only one minute. Can we wonder, then, that Leonardo was anxious to learn what seemed to him to be a wonderful trick in the multiplication of numbers?

How do you think the Moorish schoolmaster proceeded? Of course we do not know exactly, but we know how Leonardo gave the 65