Math Crossword Puzzle

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Across
  1. 3. Contains only numbers and operation symbols
  2. 4. Educated guess
  3. 5. The number of times a digit is multiplied by itself
  4. 7. To solve; find the value
Down
  1. 1. The answer to a multiplication problem
  2. 2. The answer to a subtraction problem
  3. 6. The answer to an addition problem