Are you a Mathematician?

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Across
  1. 4. f(0)=0
  2. 6. Z
  3. 7. typically 95%
  4. 9. how do you turn root beer into beer?
  5. 10. the number eight taking a nap
  6. 11. the weirdest set of numbers
  7. 13. ___Celsius
  8. 14. when someone is not being reasonable
  9. 15. a^2+b^2=c^2
  10. 17. ≈
  11. 19. you can also eat it
Down
  1. 1. synonymous to slope
  2. 2. 1;1;2;3;5;8
  3. 3. ^-1
  4. 5. Greek mathematician
  5. 6. if ae=a, then e is an___
  6. 8. Which tree is a math teacher's favorite?
  7. 12. not first, but not last
  8. 14. how to turn a French fry into a potato
  9. 15. smile/frown
  10. 16. "The limit does not exist!"(Mean Girls reference)
  11. 18. i