Multiplying fractions is junk knowledge, so the TES told me this week.
That’s junk knowledge that enables someone to work adeptly with number.
That’s adeptly working with number that enables someone to abstract with algebra.
That’s algebraic abstraction that enables someone to understand calculus.
That’s understanding calculus that allows someone to become, say, an engineer.
That’s becoming an engineer that enables someone to design the building (and model and analyse its perfect conditions) that houses the servers on which the TES is located.
All so someone on the TES can call multiplying fractions ‘junk knowledge’.
I thought of lots of loops through mathematical knowledge with this same start and finish. It was quite good fun.