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.
Algebraic expression. In mathematics, an algebraic expression is an expression built up from integer constants, variables, and the algebraic operations (addition, subtraction, multiplication, division and exponentiation by an exponent that is a rational number). For example, â + is an algebraic expression. Since taking the square root is the same as raising to the power , â + is also an algebraic expression. By contrast, transcendental numbers like Ï and e are not algebraic. A rational expression is an expression that may be rewritten to a rational fraction by using the properties of the arithmetic operations (commutative properties and associative properties of addition and multiplication, distributive property and rules for the operations on the fractions).