I follow actively your Youtube channel as well as I have your apps on my phone/iPad as well (you did a fantastic job 😊...).
During my active professional life (I am retired now and I was Regulatory Affair Director in a large Chemical company), I interviewed many (probably around a hundred) young applicants for various jobs, mostly in the end at the PhD levels.
They were supposed to be good at math and, sometimes, when I wanted to investigate a little more on their personalities I asked them to perform a tittle test (pasted below). I told them: it’s very basic, only addition and multiplication and you will find the solution in less than a couple of minutes, but….
Once they read the test, usually the applicants started to sweat a little, get confused and most of them lost their logic.
Obviously, after a while, I had to explain the true purpose of the test: I did this not to test their math skill but, only to get a short hint at how they would perform under stress. Usually that was quite informative. I thought that could be of interest to you. Best regards and keep going (best luck if you have to relocate).
“This year's Bac S math test!
3 men go to a hotel. The receptionist announces the room at 30€.
So each gives 10€.
A little later, the receptionist realizes that the room is actually 25€.
He calls the bellman and sends it with the 5€ to the men who rented the room.
On the way, the groom wonders how he will share the 5€ in 3. He decides to give each person 1€ and keeps 2€ for him.
So each of the 3 people paid 9€ for the room; this makes a total of 27€.
Add to these 27€ the 2€ kept by the bellhop; that's 29€.
Where is the other euro?”