number | System Class |

**Class Precedence List****Description**The

*type***number**contains*objects*which represent mathematical numbers. The*types***real**and**complex**are*disjoint**subtypes*of**number**.The

*function***=**tests for numerical equality. The*function***eql**, when its arguments are both*numbers*, tests that they have both the same*type*and numerical value. Two*numbers*that are the*same*under**eql**or**=**are not necessarily the*same*under**eq**.**Notes**Common Lisp differs from mathematics on some naming issues. In mathematics, the set of real numbers is traditionally described as a subset of the complex numbers, but in Common Lisp, the

*type***real**and the*type***complex**are disjoint. The Common Lisp type which includes all mathematical complex numbers is called**number**. The reasons for these differences include historical precedent, compatibility with most other popular computer languages, and various issues of time and space efficiency.