Math crossword puzzle

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Across
  1. 4. numerals
  2. 7. Two lines that meet
  3. 10. a polygon having four sides
  4. 13. a triangle with no equal sides
  5. 14. used to tell time
  6. 16. a type of triangle that has all equal sides
  7. 17. An arrangement of objects, pictures, or numbers in rows and columns
  8. 19. Find the difference
  9. 20. the two numbers added together
Down
  1. 1. a coin worth 25 cents
  2. 2. Find the product
  3. 3. Find the sum
  4. 5. a type of triangle that has any two sides equal in length
  5. 6. three sided shape
  6. 7. Two lines that are the same side by side
  7. 8. the result of multiplication
  8. 9. the flat surface of a solid shape
  9. 11. a coin worth 1 cent
  10. 12. a coin worth 10 cents
  11. 15. a coin worth 5 cents
  12. 18. used to measure