It is a common practice to number provisions in some way, in particular to make reference from one to another easier. But not all contracts include such internal references.

Numbers can be written either as words (e.g., one hundred) or numerals (e.g., 100). In this article we follow the guidelines of APA Style, one of the most common style guides used in academic writing. In general, words should be used for numbers from zero through nine, and numerals should be used from 10 onwards.

Fortunately, the rules about numbers in writing are much easier — and more scintillating — than the definitions of words related to numbers. The Chicago Manual of Style, The Bluebook and the ALWD Guide to Legal Citation all suggest spelling out numbers from zero to ninety-nine.

Contract Number means, with respect to any Contract included in the Trust, the number assigned to such Contract by the Servicer, which number is set forth in the related Schedule of Contracts.

For whatever reason, when attorneys draft contracts they don't just write the numerals like regular people. Instead, attorneys typically write out numbers in words as well as add the numerals in parentheses. For example, instead of writing “45 days”, an attorney would write “forty-five (45) days”.

You can number sections consecutively (i.e. 1., 2., 3. or (1), (2), (3)) or you can number the articles and sections using a multiple-numeration system (i.e. the sections of article 2 being numbered 2.1, 2.2, 2.3).

If the number is approximate (e.g. 'around six hundred years ago') it should be spelled out. Very large numbers should generally be expressed without using rows of zeros where possible (e.g. $3.5 million instead of $3,500,000). In contracts, the use of both words and numbers is common in order to increase certainty.