Number Roots

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Across
  1. 2. a ten footed creature, such as a crab or shrimp
  2. 3. a period of 100 years
  3. 4. a polygon (shape) having five sides
  4. 5. a forty-year-old
  5. 6. a three-pronged spear
  6. 8. a four-footed creature
  7. 9. the Ten Commandments
Down
  1. 1. an insect with many legs
  2. 5. one of five babies born at one birth
  3. 7. a series of three books or plays