Math puzzle

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Across
  1. 4. all positive numbers and zero
  2. 9. a monomial or sum of monomials
  3. 10. the line that divides the coordinate plane into two half planes
  4. 13. a part of a coordinate plane on one side of the line
  5. 14. one term
  6. 15. include one or more variables
  7. 16. two terms
  8. 17. parts of a math expression
  9. 18. math phrase that combines numbers and/or variables
  10. 19. four terms
  11. 20. any numbers that can be written as a fraction
Down
  1. 1. all positive numbers
  2. 2. the coefficient of the 1st term of the polynomial written it standard form
  3. 3. Real numbers that are not rational
  4. 5. any number that can be plotted on a number line
  5. 6. three terms
  6. 7. when two inequalities are combined into one statment
  7. 8. the numerical factor in a variable term
  8. 11. contains only numbers
  9. 12. all positive and negative numbers and zero