Challenge 4

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Across
  1. 2. form of measuring distance
  2. 3. a number system using base-10
  3. 6. any number from 0 to 9
  4. 8. what you write at the top of a paper
Down
  1. 1. three sided shape
  2. 4. a whole number that includes positive and negative numbers
  3. 5. putting two things together
  4. 7. something you do with a door