Let's say I learnt some formulae to solve permutations and combinations. I am trying to learn it by myself, when I think I've already learnt the principle and I can make use of inductive thinking to cope with all the problems about both issues, I find problems I can't solve, and when I go back from scratch and see how someone else solved the problems I only find different gaps I had not filled in my mind to understand the complexity of these topics and I think I build a more complex understanding, and again fail with problems I think at this stage I would be able to solve. I conclude saying I need to work more on that, but I've thought I had learnt something so I did not realize about my limitations till I was challenged.