Use the full section span

Warning²Federal courts, Illinois courts21st and 22nd editions

A span of sections keeps every digit, because a section number identifies a provision rather than a position in a volume: “§§ 1924-1999”, not “§§ 1924-99”.¹

1. 1R. 3.3(b) Multiple sections and subsections.
2. 2A warning: the form is usually wrong under the rule in note 1, and context can justify it.