plic ply crossword

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Across
  1. 2. what does plic/ply mean
  2. 3. the process of adding a number to itself
  3. 5. to make an exact copy
  4. 7. makes something difficult
  5. 9. a clearness in communication
Down
  1. 1. increase the amount of something
  2. 4. a person who helps
  3. 6. simple or easy to understand
  4. 8. to put use