An equation is a mathematical statement that asserts the equality of two expressions. It contains an equals sign (=) and shows that the values on either side of the equals sign are the same. For example, in the equation 2x + 3 = 7, the left side represents an expression that equals 7.
On the other hand, an expression is a combination of numbers, variables, and operators (such as addition, subtraction, multiplication, and division) that represents a value but does not include an equals sign. For example, 2x + 3 is an expression. It can be simplified or evaluated for specific values of the variable but does not assert a relationship of equality.
In summary, the key difference is that an equation expresses a complete thought that equates two expressions, while an expression merely represents a value without claiming equality.