Equations

5. two operations which are exactly opposite. One undoes the action of the other
6. find a numerical expression or equivalent for (an equation, formula, or function)
9. a mathematical statement that shows that two mathematical expressions are equal
10. defining something as a modification of another thing
11. the part of mathematics in which letters and other general symbols are used to represent numbers and quantities in formulae and equations

1. an integer that is written along with a variable or it is multiplied by the variable
2. arranged in or extending along a straight or nearly straight line
3. a pair of numbers whose sum is zero
4. a value that doesn't change
6. a sentence with a minimum of two numbers or variables and at least one math operation
7. an alphabet or term that represents an unknown number or unknown value or unknown quantity
8. a system by a set of variables and a set of equations that establish relationships between the variables