Number crossword

12345678910111213141516
Across
  1. 2. Number in a quartet (4)
  2. 5. The age when you can vote (8)
  3. 8. 0 goals in soccer (3)
  4. 9. 2 + 3 + 5 (3)
  5. 11. A quarter of twelve (5)
  6. 12. Numbers like 2,4,6,8,10 (4)
  7. 14. 6 + 5 - 4 (5)
  8. 15. Half ______ six is 3 (2)
Down
  1. 1. One of two that look alike (4)
  2. 3. 278 + 131 - 408 (3)
  3. 4. 173-162 (6)
  4. 6. 12 ➗ 6 (3)
  5. 7. Not any (4)
  6. 10. 63 ➗ 7 (4)
  7. 11. 5 x 4 (6)
  8. 13. Short for 'number' (2)
  9. 14. 17 - 11 (3)
  10. 16. One sixth of thirty (4)