A fun anecdote: I taught him some machine learning for an afternoon! He used to spend a few months per year in Oxford, and he had gotten in touch with my PhD advisor to ask some ML questions, as at the time he was writing his new book about linear algebra and learning from data. My advisor couldn't make it to their meeting so he sent me at the last minute instead. So bewildered me, a PhD student, met with Gilbert Strang to explain him some basic machine learning concepts! Interestingly, whenever I'd asked if he was already familiar with some concept, he'd always say no, which I suspect was a strategy to hear it explained in new words.

Anyway, Gil is a very polite and kind person, his encounter will stay a great memory.