The expression "4 - 1" represents a simple mathematical operation known as subtraction. In this case, the number 4 is the minuend, and 1 is the subtrahend. When you subtract 1 from 4, you are determining how much remains after taking away 1 from 4. The result of the operation "4 - 1" is 3. This means that if you start with 4 items and remove 1 item, you will have 3 items left. Subtraction is a fundamental arithmetic operation used in various everyday situations, such as counting, budgeting, and measuring.