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.
Formula, expression, identity, equation? Do you understand the difference between a formula, expression, identity and equation? A formula is a rule written using symbols that describe a relationship between different quantities. An expression is a group of mathematical symbols representing a number or quantity. Expressions never have equality or inequality signs like =, >, <, â  ,â¥ ,â¤. Some examples. 3a. 3xy + 4x. tÂ² + tÂ³. An identity is an equation that is always true, no matter what values are chosen. Examples. 3a + 2a = 5a. xÂ²+xÂ² = 2xÂ². 5 x 10 = 10 x 5. An equation is a mathematical statement that shows that two expressions are equal. It always includes an equals sign.