vb. 1. (of an algebraic or arithmetic expression) to have as its value, the latter being specified as some other arithmetic or algebraic expression. Thus, the result of a computation, or the solution of an equation are written as, for example, 7 + 5 = 12 and x = 5 respectively. 2. (of two mathematical expressions) to refer to the same quantity or entity; for example x² + 2y = 2x + y² when x equals y. See equation, identity.