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?

Can you move 2 matchsticks to form four equal sized squares.

Can you name three consecutive days without using the words Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, or Sunday?

By removing one matchstick and adding one matchstick, can you convert the word "ZOO" to an animal name?

If nine thousand, nine hundred nine dollars is written as $9,909,
how should twelve thousand, twelve hundred twelve dollars be written?

If two's company, and three's a crowd, then whats four and five ?

You are presented with three boxes. One of them has a red ball inside and the other two have a black ball inside each of them. You are asked to pick up the one with red ball and you pick one. Now, one of the other boxes is opened and it is found to have a black ball.

You are presented with a chance to change your box with the one that is left closed. Will you change your box? Why or why not?

What is always in front of you but can’t be seen?

Can you complete the sequence?

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

When it's bad luck to meet a black cat?