22.

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Across
  1. 3. "We have met the enemy" there
  2. 5. "New Math" songwriter Tom
  3. 7. 1934 Public Enemy #1
  4. 8. 007 enemy
Down
  1. 1. Actress Clarke of "Public Enemy"
  2. 2. Popular university dons fix math question number
  3. 4. Maths question
  4. 6. An enemy of Sparta
  5. 8. A diehard enemy might want yours
  6. 9. 1960's enemy capital