Blakes puzzle

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Across
  1. 3. a line you can put numbers on for a problem
  2. 4. the distance between a number and zero on a number line
  3. 5. switch the numbers
  4. 7. The set of whole numbers and their opposites
Down
  1. 1. a numbers opposite
  2. 2. if more than two integers you can rearrange the the order
  3. 6. a number that can be written as A over B were A and B are integers