Okay, I already finished every single intermediate puzzles and am into the advanced ones with no problem. I understand every single other tutorial puzzle except this one. The blue square is a 4...but how? If I can do the puzzles no problem, I should be able to understand this one!! O_O.
PS: I saw in the other topic that a lot of people are having trouble writing the 4. This is how I do it, and it works 100% of the time, every time: