Algebra assignment puzzle

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Across
  1. 4. inverse when the product of two numbers is 1
  2. 6. (x,y) the location of a point on a grid
  3. 8. a non-ending decimal
  4. 9. the result of a multiplication problem
  5. 10. when you add the same numbers to both sides of an equation and the two sides are still equal
  6. 11. when the sum of two numbers is 0
  7. 13. parts of an equation or expression
  8. 14. the number in front of a variable
  9. 16. the four regions on a grid
  10. 17. the distance around a figure
Down
  1. 1. when you multiply the same number to both sides of an equation and the two sides are still equal
  2. 2. the result of an addition problem
  3. 3. when you can multiply three or more numbers and the order doesn't matter
  4. 5. when you can add to numbers and the order doesn't matter
  5. 7. and ending decimal
  6. 12. the amount of surface
  7. 14. A number by itself
  8. 15. (0,0)