In mathematics, a field is a certain kind of algebraic structure. In a field, one can add (), subtract (), multiply () and divide () two numbers (with division only possible if is non-zero). A field is a special ring in which division is possible. Both the set of rational numbers and the set of real numbers are examples of fields. The set of integers, , is not a field, because the result of a division is not always an integer. One can also use the symbol as a variable for a field.[1]