Number prefixes

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Across
  1. 5. dress code at school
  2. 6. space, matter, time and ourselves
  3. 9. a group of three musicians
  4. 13. to bring together; become one
  5. 15. made of three parts
  6. 16. relating to the heart
  7. 17. a three-legged apparatus; (music stand)
  8. 18. the process of breathing
Down
  1. 1. to divide into two parts
  2. 2. relating to the lungs
  3. 3. father, son, and the holy spirit
  4. 4. two times a week
  5. 6. a place of learning; college
  6. 7. to sing simultaneously
  7. 8. process of sweating
  8. 10. optical device with two lenses
  9. 11. code made up of 1's and 0's
  10. 12. walks on two feet
  11. 14. group of three eighth notes
  12. 17. a group of three things (movies & games)