2 step equation

1234567891011
Across
  1. 2. A letter that a hidden number
  2. 5. A statement that has answer
  3. 6. the part of mathematics that helps represent problems or situations in the form of mathematical expressions
  4. 7. the number that represents no amount or no objects
  5. 10. the opposite
  6. 11. A model that repents something
Down
  1. 1. straight line graphs to represent the relationship between two quantities
  2. 3. a number or symbol by which another number or symbol
  3. 4. finding the numerical value or result of a mathematical expression or equation
  4. 5. any mathematical statement which consists of numbers, variables and an arithmetic operation between them
  5. 8. the values on which mathematical operations occur in an algebraic expression
  6. 9. something invariable or unchanging