Math Ain't Adding Up...Or is it?

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Across
  1. 2. Subject
  2. 4. Money
  3. 6. Triangle
  4. 7. Not odd
  5. 9. Box
  6. 11. 10/2
  7. 12. Times
Down
  1. 1. Data
  2. 3. Shape
  3. 5. Add
  4. 8. 4+4
  5. 10. Basketball
  6. 12. Average
  7. 13. Straight