Hello, Gary, and welcome to the Grammar Exchange.
@Gary C123 posted:
"The total drinks that I consumed during the night was seven."
"The total drinks that I consumed during the night were seven."
I want to say that "was" sounds more natural to me (for whatever possibly illiterate reason), however, if "drinks" is the subject, it seems like it should be "were".
It sounds more natural to you because, as you indicated in your post, the singular noun "number" is missing.