67 Maths Puzzle 67

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Across
  1. 2. Five, ___, Seven
  2. 3. One, ___, Three
  3. 5. Eight, ____, Ten
  4. 6. Three, ____, Five
  5. 7. Seven, _____, Nine
  6. 9. Six, _____, Eight
Down
  1. 1. Four, ____, Six
  2. 3. Two, _____, Four
  3. 4. Zero, ___, Two
  4. 8. Nine, ___, Eleven