Equation: meaning, definitions and examples

Use this term when referring to a mathematical sentence that shows the equality between two expressions. It typically contains an equal sign (=).

• The equation x + 2 = 5 can be solved by subtracting 2 from both sides.
• In physics, we use the equation E = mc^2 to relate energy, mass, and the speed of light.

Use this word when referring to a specific rule or relationship expressed in mathematical symbols, often used to calculate something. Formulas are widely used in various fields such as physics, chemistry, and finance.

• The formula for the area of a circle is A = πr^2.
• In chemistry, the formula for water is H2O, indicating that each molecule contains two hydrogen atoms and one oxygen atom.

This term is appropriate when referring to a combination of numbers, variables, and operators that represent a value. Unlike equations, expressions do not have an equal sign.

• Simplify the expression 3x + 4.
• In algebra, an expression like 2a + 3b can be evaluated by substituting values for a and b.

This term is general and can refer to any declarative sentence in mathematics that is either true or false. It is more formal than the other terms and can encompass equations, inequalities, and logical statements.

• The mathematical statement 'The sum of the angles in a triangle is 180 degrees' is always true.
• ‘5 > 3’ is a simple mathematical statement indicating that 5 is greater than 3.