Addition and subtraction

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Across
  1. 2. Seven _____ two makes five
  2. 4. Thirteen minus one
  3. 6. Five plus two plus one
  4. 9. Ten minus four
  5. 12. Seven minus four
  6. 13. Three plus four is _____ to five plus two
  7. 15. Six plus seven
  8. 16. Seven plus four
Down
  1. 1. Ten plus seven
  2. 3. Seventeen plus two
  3. 5. Eight plus eight
  4. 7. Ten plus ten
  5. 8. Eight minus four
  6. 10. Four ____ four makes eight
  7. 11. Nine minus four
  8. 14. Four plus five