Math time!

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Across
  1. 3. a repeat button's broken
  2. 4. i go up and down
  3. 5. value some high some poor
  4. 6. x and y's no lies
  5. 9. seems like another language to some
  6. 11. i make things big
Down
  1. 1. something teenagers feel is useless
  2. 2. vortex's sister
  3. 3. ups and downs in life
  4. 7. the middle child
  5. 8. i should sue them
  6. 10. used to eat on