Analytic vs. algebraic perspectives
"analytic number theory exists and involves calculus, but it's not what the linked post is about. The article talks about Hensel's lemma, which is a purely algebraic statement with a purely algebraic proof, which, however, is inspired by techniques from calculus." – arch1t3cht
Calculus‑inspired conceptual bridge
"It's delightful (and unsurprising) that Newton's method shows up as the main bridge." – adampunk
Misleading title/Expectation of calculus
"In some sense the title is a bit misleading... I'd rather use the title "Using differentials to...", which is more precise, as there is not exactly any "calculus" going on but there is indeed differential algebra and differential "number theory", so to speak." – pfortuny