Maths isn't most people's strongest point, but I find Asians tend to do much better than Caucasians, at least in UK.
One time our supermarket bill came to something like £16.20 so we gave the cashier £21.20. Poor girl was so confused, gave the £1.2 back to us, and £3.80 change 🙃
The same situation with an Asian cashier, and she got it immediately.
I don't know if it's a cultural thing but there's some dumbasses out there that's for sure. Not so long ago I actually asked the cashier to count back my change so I knew she got it right. She tried twice and was way off and than I took pity on her and said, just dump it in my hand, I haven't got the time. A sad indictment of the state of play these days.