Why is a river so rich ?
A network of 20 x 10 squares is given to you. Can you calculate how many unique squares and rectangles can be formed combining two or more individual squares ?
Twenty frogs are sitting on a log floating on the surface of a river. Two of them decide to jump off into the water. How many frogs are there on the log at this moment?
I travel all around the world but always stay in the corner. What am I?
The more of this there is, the less you see. What is it?
I am quite hot but become too cold if you remove the first two letters. What am I?
In a boat, the father of a sailor's son is sitting with the son of the sailor. However, the sailor is not present on the boat. Can this even be possible?
You want to boil a two-minute egg. If you only have a three-minute timer (hourglass), a four-minute timer and a five-minute timer, how can you boil the egg for only two minutes?
Can you write down eight eights so that they add up to one thousand?
Can you solve the below tricky visual equation?
What mathematical symbol can be put between 5 and 9, to get a number bigger than 5 and smaller than 9?
In the 1920s, people feared that crossword puzzles would contribute to illiteracy.
