For the first five IMO problems, the speaker says the solution can generally be decomposed into steps such that solving each step solves the overall problem.

“uh that is the minimal bound or like the upper bound it's the lower bound of the upper bound then ai kind of sucks at that and so i think um this is why no ai can solve the last problem but it also is super hard for human as well and like if you look at the first five problems you can basically when you look at a problem you already know how to decompose”

“the uh how to discompose a problem into several steps and then you know that if you can solve each step then you can solve the whole problem but then for the last problem you kind of need to do a lot of uh experiments or like you need to look at the smaller examples and”