There is an English word that can be used up to four times in a row without modifying the spelling and form a valid grammatical sentence.

Do you know what word is that?

What is the four-digit number in which the first digit is one-third the second, the third is the sum of the first two, and the last is three times the second?

Rectify the following equality 101 - 102 = 1 by moving just one digit.

Can you decipher the two rows to find the hidden word?

In the image below, you can see two glasses and two matchsticks.You need to move four matchsticks in such a manner that the crosses come inside the glasses. Note: you cannot move the crossed.

The first box has two white balls. The second box has two black balls. The third box has a white and a black ball.

Boxes are labeled but all labels are wrong!

You are allowed to open one box, pick one ball at random, see its colour and put it back into the box, without seeing the colour of the other ball.

How many such operations are necessary to correctly label the boxes?

How high do you have to count before you use the letter “a” in the English spelling of the whole number?

A man who was outside in the rain without an umbrella or hat didn’t get a single hair on his head wet. Why?

Paul's height is six feet, he's an assistant at a butcher's shop and wears size 9 shoes. What does he weigh?

I am taken from a mine and shut up in a wooden case, from which I am never released, and yet I am used by almost every person. What am I?