She looked at him curiously - at his ugly tweed suit, his yellow boots, and up into the strong, forceful face with eyes set in deep hollows under his protruding brows, at the heavy jaws giving a certain coarseness to his expression, which his mouth and forehead, well-shaped though they were, could not altogether dispel.
Definition of Expression. An Expression is a mathematical phrase that combines numbers and/or variables using mathematical operations. An expression is a representation of a value; for example, variables and/or numerals that appear alone or in combination with operators are expressions.
Expression and Equation are terms that are very often encountered in mathematics. However, if you were to ask the difference between an expression and an equation to even those who are students of Math, chances are you may not get a satisfactory answer. Both are however important in understanding different concepts in Mathematics.