Where do math symbols come from?

Edit Answers
1234567891011121314151617
Across
  1. 5. (verb) To make something shorter in time or length.
  2. 6. (noun) A large amount of money, property, or valuable things that someone owns.
  3. 8. (adjective) Also can mean appropriate or suitable.
  4. 9. (adjective) Difficult or impossible to read.
  5. 10. (adjective) Said in a clear and short way, without unnecessary words.
  6. 13. (verb) To meet or come across something or someone, often unexpectedly.
  7. 14. (phrasal verb) To replace or take the place of someone or something.
  8. 16. (adjective) Based on personal choice or chance, not on reason or rules.
  9. 17. (verb) To start or come from a particular place or situation.
Down
  1. 1. noun) A small letter or number written just below the normal line of text. Often used in math or science.
  2. 2. (verb) To feel curious or surprised about something.
  3. 3. (adjective) Very long, especially in time or words.
  4. 4. (noun) Behaviour that follows rules or the usual way of doing things.
  5. 7. (phrasal verb) To begin to understand something or realize what is happening.
  6. 10. (noun) A small letter or number written just above the normal line of text. Often used in math or citations.
  7. 11. (noun) A quick way of writing using symbols or abbreviations, often used for taking notes.
  8. 12. (noun or adjective) A level of quality or a rule that is accepted and used by most people.
  9. 15. (adjective) Heavy, large, or difficult to carry or use.