Comma with a Number or Letter Used to Denote a List Item
The Comma
Rulebase Summary
When a number or letter is used parenthetically to delineate items in a series, use a comma after it at the beginning of the sentence and before it at the end. Words like 'first,' 'firstly,' 'last,' and 'then' used to denote items in a listing follow this same rule. When the number or letter is in the middle of the sentence, it is surrounded with commas.
Examples
A. First I was not aware of the arrangement at the time.
A. First, I was not aware of the arrangement at the time.
'First' denotes a list item — comma after it.
A. He was not two at all prepared for the examination.
A. He was not, two, at all prepared for the examination.
Number denoting a list mid-sentence is surrounded with commas.
Transcript Notes
Numbers, letters, and ordering words (first, firstly, last, then, secondly) used to denote list items are parentheticals. When they appear mid-sentence, they are surrounded with commas.
Style Guide References (4)
BGGP
BGGP
BGGP
BGGP