I was in a bit of a weird half-rate math competion team/club where some people who were there to get out of history class and some people who were very much the opposite and were some of the smartest people I've ever talked to. One thing I noticed is that all the power competitors had good calculation ability, but whereas some people were just really fast calculators and, like your lab friend, could calculate huge multiples in their head, others were actually subpar at that type of mental math and instead were just familiar with, for instance, all the perfect squares/cubes/powers of 5 up to 20 and beyond because they've just encountered them a lot.