Expressions and Equations

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Across
  1. 2. replace a letter with a number
  2. 5. a symbol for an unknown value
  3. 7. remove brackets
  4. 8. a single mathematical expression
  5. 9. insert brackets
Down
  1. 1. a statement to show two expressions are equal
  2. 3. a combination of numbers and letters
  3. 4. a number before a variable
  4. 6. what we call addition/subtraction etc