Evolution, when applied to humans, is something that takes a lot longer then 300 years to achieve. It's not "evolution" to give someone advanced technology and teaching methods and sit back and be impressed that they can do calculus at age 10.
Human history has many examples of people who were very smart, but didn't make the same discoveries we know about today, simply because they lacked the technology/tools/resources to make it possible in their time period.
If 300 years makes that much of a difference in inherent human intelligence, that doesn't bode well for the 20th century people rescued from cryogenic freeze, or even Gillian Taylor. By your reckoning, they'd all be too stupid to get anywhere, or learn what they would need to know to function in the 23rd/24th century societies.
Anyone going from the 20th century to a far-later one is certainly going to have some culture-shock, that's a given. (Ditto for Doctor Who companions leaving the Doc after finding someone to love in a society form Earth's past, or if they opt to leave to run an entire alien society on a whim.) It's sad that the schmaltzy and syrupy end-of-story scenes write it off; so many sequels of characters regretting their hyperactive hormones or whatever caused them to vamoose would be refreshingly different for television, but before I digress:
TNG was doing the schmaltzy shtick because they wanted to make the housewife lady jump over a Klingon and to make Picard and Troi look like doofuses when dealing with the Romulans, since Romulan chess never gets old. So at least Offenhouse could do Troi's job and he's just some ancient throwback that Picard does the usual season one "we're more evolved" haughty routine at (not since "Lonely Among Us" has there been such a great example, noting in both stories characters make some interesting retorts), but I'm sure the need to understand the underlying logic behind maths is going to be important for some venues.) That said, at least with Gillian, she'd be tending to the whales. Of course, if she felt like she had nobody on Earth in 1986, once Kirk flies off to hop some more galaxies instead of her, she won't feel any different.
KIRK: Where would the whales be by now?
GILLIAN: Please, do you have a chart on board? I'll show you.
KIRK: No, no, no. All I need is the radio frequency to track them.
GILLIAN: What are you talking about? I'm coming with you.
KIRK: You can't. Our next stop is the twenty-third century.
GILLIAN: I don't care? I've got nobody here. I have got to help those whales.
I bet she's fibbing about having nobody, but until a sequel or novel confirms that and such a novel would probably take the least creative explanation as well... but the point reminds, TNG's excursion of bring in 20th century people into the future as plot fodder didn't really do much more except to make Picard bad, since no other reason comes close. Then again, I bet Picard had to learn at least basic algebra at some point, despite not needing it later on.
How the kid was going to learn calculus; by pencil and paper or by the ship doing it. I may have wrote hat point I made earlier incorrectly; given the advanced technology they're all stuck in, everyone would have to know the basics of how it's constructed earlier in life. Not the technology doing the work for them since, if the technology fails, who'll repair it?
Then again, the need to know math is greatly diminished for many jobs nowadays as the computer does the work (the scene in TNG definitely is outdated), and in Trek the story "Datalore" shows the adults to be a boatload of twit - which is at variance with other episodes. Season 1's inconsistency is the one thing I think is the ultimate in stupidity inasmuch as it's also exploring different formats. But they can still do a whodunnit without making the adults a bunch of dingalings. )
At least it wasn't Wesley who saved the ship by using calculus - part of me sorta likes to think that lots of kids.
Even more fun: At least everyone's talking about when it's appropriate to teach young kids advanced mathematics principles based on an episode that's roughly 35 years old. I'll concede that, either way, it can't be
that bad...
Addendum:
https://www.quora.com/At-what-age-do-kids-in-different-countries-learn-calculus ,
https://www.edn.com/can-11-year-olds-learn-calculus/, etc... but it's interesting.