I think the bottom one may be some sort of combinatorics

I really like the top right of the bottom blackboard…

“If we think very hard about it and break the fundamentals of math, logic and everything else we know about the universe, down into the most crucial and elemental components we may be tempted to come to the conclusion that 5 is - maybe somewhat simplified - just five 1s added together, basically.”

I’m sure that there’s probably more going on here… maybe…

5 = 5 = 4 + 1 = 3 + 2 = 3 + 1 + 1 = 2 + 2 + 1 = 2 + 1 + 1 + 1 = 1 + 1 + 1 + 1 + 1

Riveting stuff

Not my experience as an actuarie. In college all the models and examples you learn are based on the platonic insurance company where everything works perfectly. In the real life, everything is a mess and the models hardly work and you had to crack workarounds for everything.