all words are made up of the -ation suffix

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Across
  1. 6. when someone thinks of something they make up
  2. 7. it was found by Marie Curie
  3. 8. when you give something to people in need
  4. 10. a celebration after finishing year 12
Down
  1. 1. it is the second word in the clue for across number 10
  2. 2. to turn into something
  3. 3. when you ask someone to keep something aside until you get there
  4. 4. some words which have the same letters at the start of each word
  5. 5. multiplication, division, subtraction and...
  6. 9. to make something