I used to be bemused at the concept of an adult who couldn't drive, or swim, or was a graduate but claimed they couldn't do maths.
In the country where I grew up, public transport and even taxis weren't an option. If you couldn't walk/bicycle/motorcycle/drive or get a lift to where you wanted to go, you didn't go. I don't recall ever coming across an adult who couldn't drive. (I guess those with epilepsy/whatever crossed their fingers and drove anyway. Officialdom probably wasn't organised enough to prevent them.)
Every school, both state and private, had at a minimum a half-Olympic size pool. I recall earning life-saving badges in the one at my free state primary. That was voluntary, and my parents paid for a handful of lessons at the municipal pool that were all I needed to make me drown-proof. There was compulsory swimming of lengths in both primary and secondary PE lessons. I am bemused whenever I hear news reports of someone in the UK drowning in a canal or river. I can understand drowning in the sea where the current can keep you away from the shore, but it requires a conscious effort to imagine how someone could drown in fresh water.
I hear educated and successful people in the UK not so much admit as boast that they can't do maths. The system where I grew up was that maths was a compulsory high school subject and I think that without a C in maths no university would admit you as a student. (My father, a working-class Englishman who left school at 14, passed the exams needed for divinity degree, but was awarded a diploma and not a degree because his school record didn't qualify him to be a university entrant. He would, among other things, have needed that C in maths.)
I now live in London, so can perfectly understand living without a car. I could easily do it myself.
As a relatively well-off adult, I don't have easy access to a swimming pool for doing lengths, and I've noticed that not only does not every school have one, but, having lived here for 30 years, the climate isn't exactly conducive to out-door pools. (Though having flown out of London City airport over North London a few times, I was shocked to find there are parts of the capital where every house seems to have an out-door pool. From the air it looks like lots of people think they are in Australia or California.) So, if I make a conscious effort, I can sort of grasp the concept of an adult who can't swim.
The maths thing is pure bollocks though. People don't do maths because the system (school and presumably university) allows them not to.