The expression "4 + 1" represents a simple arithmetic operation where the number 4 is added to the number 1. This operation is part of basic mathematics and is often one of the first concepts taught in early education. The result of this addition is 5. In this case, 5 is the sum of 4 and 1. Understanding addition is fundamental for more complex mathematical concepts and is used in everyday situations, such as counting objects or calculating totals. This basic operation lays the groundwork for further learning in mathematics.