Nomenclature, Classification and Codification
Each account in the chart of accounts is typically assigned a name and a unique number by which it can be identified. (Software for some small businesses may not require account numbers.) Account numbers are often five or more digits in length with each digit representing a division of the company, the department, the type of account, etc.
As you will see, the first digit might signify if the account is an asset, liability, etc. For example, if the first digit is a "1" it is an asset. If the first digit is a "5" it is an operating expense.
A gap between account numbers allows for adding accounts in the future. The following is a partial listing of a sample chart of accounts.
Read more about this topic: Chart Of Accounts