Replace the word with a numeral

Warning²Federal courts, Illinois courts21st and 22nd editions

A number of one hundred or more is written as a figure in a brief’s text — “123 pages”, not “one hundred twenty-three pages” — unless it opens the sentence.¹

1. 1B6 Abbreviations, Numerals, and Symbols. Tables: R. 6.2(a) Numerals.
2. 2A warning: the form is usually wrong under the rule in note 1, and context can justify it.