The square root of number 121 is "11". What is the square root of the number "12345678987654321."?

In two decks of cards, what is the least amount of cards you must take to be *guaranteed* at least one four-of-a-kind?

What does this rebus photo means?

What has one eye, but can’t see?

What does the below mathematical rebus mean?

Two boys wish to cross a river. The only way to get to the other side is by boat, but that boat can only take one boy at a time. The boat cannot return on its own, there are no ropes or similar tricks, yet both boys manage to cross using the boat.

How?

A man in a car saw a Golden Door, Silver Door and a Bronze Door. What door did he open first?

There is a brick of gold and a brick of iron in a boat (both 10-inch blocks), if they are both dropped into the water which will make the water level higher?

Why are televisions attracted to people?

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 ?