Logical task. There you can find mathematic riddles which have chance to see them in the schools. Mostly they are extended with some trick. More riddles you can find in this category there is better chance that some of the riddles you have not ever seen.
Mathematic is important but mostly you will need to use logic. I have tried to do my best to select only the riddles which have only one unique answer.
You can find here several number or letter sequences, some of them you will solve it using math, some of them by logic or by using little bit of associaction.
Play with numbers
Play with years
All improovments of intellect has got the base in free time.