Nothing frustrates me as much as the twisty online puzzles. Of course, they are one of the brainstorming exercises which can improve our IQs significantly. But most online riddles and tricks aren't similar to the IQ test or any Science Olympiad exams that we used to give in our school times and it surely doesn't imply that they are easy enough.
Get ready for having some brain-frying.
Maths has always been a tough job.
You have to tell what will come in the empty column.
Losing confidence already?
Why don't you solve your own problems? Urghhh!
Damn it... It wasn't any math problem. It is a five-speed gearshift.
Anyways, better luck next time.