Constant (monomial):  It is a number or value that remains always the same. Never changes.

Evaluating a variable expression: Given an expression and values for the variables, it is the process of substituting these values in the expression and simplify it following the order of operations.

Formula: Any equation which states a rule in a relationship.

Grouping symbol: Parentheses, brackets, fraction bar are grouping symbols used to enclose an expression that should be simplified before other operations are performed.

Numerical expression: Any expression naming a particular numbers; also a numeral.

Power of a number:  The product we obtain when a number is multiplied by itself a number of times; 3x3x3x3 is the fourth power of 3 or 3⁴

Quadratic formula: Solutions of a quadratic equation in the form ax² + bx + c =0 and b² - 4ac needs to be equal or greater than zero to yield real numbers.

Simplifying a numerical expression:  Changing any expression to the simplest name for its value.

Value of a numerical expression:  The resulting number of the expression.