Wiktionary
prep.phr. (context idiomatic English) to do something exactly, precisely, or in a formulaic way.
Wikipedia
By the Numbers is an album of covers performed by The Postmarks, released in 2008.
Usage examples of "by the numbers".
To clear the point a little better, I think those princes capable of ruling who are able, either by the numbers of their men or the greatness of their wealth, to raise a complete army, and bid battle to any that shall invade them.
Nor would Goldstein assess an operation by the numbers alone, or allow himself to be given a 'Stalin village' tour of operations.
You are tremendously competent, except when you fuck up, and you apparently do that by the numbers.
We've got this thing worked out by the numbers, and I mean fractions, so the fewer distractions the better.
The languages of different islands clearly resemble each other, and their differences can be measured precisely by the numbers of words that differ between them, a measure that is closely analogous to the molecular taxonomic measures that we shall discuss in Chapter 10.
She was not piloting by the numbers anymore, but by feel, by guess.
The disgrace which had been incurred by a treacherous surprise was soon retrieved by the numbers and discipline of the Romans.
The throne of Mahomet was guarded by the numbers and fidelity of his Moslem subjects: but his rational policy aspired to collect the remnant of the Greeks.