Holiday Homework Crossword Puzzle

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Across
  1. 3. Number coming with an variable in an equation
  2. 4. A structure in mathematics which consits of both X and Y.
Down
  1. 1. There are how many rational numbers between two rational numbers
  2. 2. √9 is which kind of number?
  3. 5. X Axis on the Cartisian Plane