Math
Variables and expressions.
Definition
A variable is a letter or symbol that represents an unknown or changeable value. An expression is a mathematical phrase that combines numbers, variables, and operations (like +, −, ×, ÷) but does not contain an equals sign.
Examples
Real-world.
- 1 In the expression 3x + 5, x is the variable and 3 is the coefficient
- 2 The expression 2(n − 4) represents 'twice the difference of n and 4'
- 3 If a movie ticket costs d dollars, then 4d represents the cost of 4 tickets