The expression "5 - 3" represents a simple arithmetic operation known as subtraction. In this case, it involves taking the number 3 away from the number 5. The result of this operation is 2, which is the difference between the two numbers. Subtraction is one of the four basic mathematical operations, alongside addition, multiplication, and division. It is commonly used in everyday situations, such as calculating change when shopping or determining how many items remain after some have been used. Understanding subtraction is fundamental to developing mathematical skills.