I understand the theoretical logic behind that, but I personally find it more confusing. In my experience the textbooks don't link separate topics together very well.

For example, 1st chapter in one (old) textbook introduces the equation for the area of a circle almost immediately. This is prior to any coverage of indices (exponents), Pi, variables, changing the subject of an equation, etc.

I have searched for guides on how CAIE expects topics to be linked together, but haven't found anything really satisfying. When I ask other teachers for their thoughts... They can't find the logic behind it either.

Anyway, thank you for your reply, it sounds like your experience, and the reasons given are similar/equally vague.