Chapter 20 The power of ten

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Across
  1. 2. All peoples used the decimal system in their spoken
  2. 4. Eight units are one quine plus three, written as
  3. 7. Counting is one of the few matters about which man do not
  4. 8. The camels approach with their burdens of men and
  5. 9. The oldest number system is called
Down
  1. 1. To stand for numbers, man had to think up special characters called figures or
  2. 3. There are traces of this system and the poems of
  3. 5. Tribesmen of north Africa knew all the color of the
  4. 6. Beremiz gives his second mathematics
  5. 9. Each group of five unit is called a