. Scientific American Volume 79 Number 17 (October 1898). s those already described. In the first series, com-prising numbers of two ciphers, the thumb represents11, the index-finger 12, the middle finger 13, the ring-finger 14, and the little finger 15. When multiplyingone number by another, the fingers representing therespective factors are placed together as before. Thenumber of fingers above those joined, including these,will in this case also indicate a certain number of lower fingers are, however, entirely neglected. Inorder to obtain the number of units, the fingers whichhave a
. Scientific American Volume 79 Number 17 (October 1898). s those already described. In the first series, com-prising numbers of two ciphers, the thumb represents11, the index-finger 12, the middle finger 13, the ring-finger 14, and the little finger 15. When multiplyingone number by another, the fingers representing therespective factors are placed together as before. Thenumber of fingers above those joined, including these,will in this case also indicate a certain number of lower fingers are, however, entirely neglected. Inorder to obtain the number of units, the fingers whichhave already given the number of tens are again taken,the number on the one hand being multiplied by thenumber on the other hand. The product thus ob-tained is increased by 100 and the sum added to thenumber of tens. Suppose that 13 is to be multipliedby 14. As indicated in Fig. 11, the fingers representingthese numbers are joined. Counting the number offingers above those which have been placed together,including the latter, 7 tens or 70 are obtained. Taking. Fig. 1.—Multiplying 9X9. Pig. 2.—Multiplying 9X8. Fig. 3—Multiplying 9X7.
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