Additional Math Terminology: It is also valuable to revisit mathematical terms often used in equations. Understanding each component's role in the equation will help you set up and compute equations with confidence. Table B lists key terms and examples. Table B: Simple Equations Terminology Variable A letter (or symbol) used to represent a numerical value x, y Constant A value that does not change, usually a number x + 6 6 is a constant x is a variable Term Can be a variable, constant, or product of a constant and a variable 7x + 42 + y 7x, 42, and y are all terms Expression A mathematical phrase with numbers, variables, and operations that show the value of something. Expressions do not have an equal sign. 7x + 42 + y altogether, this is an expression; but 7x, 42, and y separately are considered terms Like Terms Terms that can be combined; helpful to simplify algebraic expressions 2x + 3x +6 = 21 5x + 6 = 21 2x and 3x are 'like terms' since they are both products with x. Add them to make 5x Equation A statement that shows two expressions are equal to each other. Equations always have an equal sign. 2x + 3x +6 = 21 this whole statement is an equation