[dynamic_sausage]

Not all mathematicians are bad at arithmetic. Both Euler and Gauss were brilliant calculators. Another comment mentions Ramanujan. In more recent history, Arnold in his exams would give problems with plenty of arithmetic estimates, that had to be performed orally and be within 10% of the exact answer.

In a surprising turn of events, people studying mathematics are a large group, and some of them are indeed incapable of factoring 57.

[__MatrixMan__]

The question in the article title sounds to me like:

> Why are people from the USA bad at navigating the New York subway?

And you're right to point out:

> People from New York aren't.

If people are surprised by the idea that many mathematicians are bad at arithmetic, then I'm guessing they also think that arithmetic is taught first because it's fundamentally foundational, rather than something to do with Diophantus having lived before Erdős.

[wrycoder]

51 looks kinda prime, too.

[mdp2021]

Well, theoretical studies teach you about navigating, managing and creating complex structures;

life teaches you to distrust and verify all appearances.