A chess tournament is taking place on knock-out terms (the one who loses the match is out of the game).
(a) If 10 matches are played in total, how many players participated?
(b) If 20 players took part in the tournament, how many matches were played?

Imagine a box with two cogwheels, one big with 24 teeth and one small with 8 teeth. The big one is firmly attached to the center of the box which means it does not turn or move while the small one rotates around the big one.

How many times do you think that the smaller wheel will turn compared to the box when it turns once around the big one?

You are playing a game with your friend Jack. There are digits from 1 to 9. You both will take turn erasing one digit and adding it to your score. The first one to score 15 points will win the game.

Would you want to play first or second?

PS: The sum should be exactly 15.

Things are just as they seem, right? Well, check again.
Can you count the number of tigers in this picture ?

I have an eye but still cannot see.

Who am I?

Which alphabet letter is a question?

Can you complete the sequence?

192, 021, 222, 324, 252, 627, 2__, 9__?

What is the coolest letter in the alphabet?

In case you were starting to feel confident, this one was meant for third graders in Vietnam. The answer is 66, but we don't blame you for scratching your head about how they got there.

I’m light as a feather, yet the strongest person can’t hold me for five minutes. What am I?