A word I know has six letters it contains, remove one letter and 12 remain. What is it?

Can you solve this amazing hard number series problem?
7, 8, 10, 12, 16, 18 ?

Forwards I am heavy, backward I am not. What am I?

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?

What is the word or phrase below?
R | E | A | D

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

Solve this riddle by finding the odd one out from the rest.

If you read clockwise, you can form a word by inserting three missing letters in the picture given below. Can you do it?

"That Restaurant always remains crowded. This is the reason why nobody goes there".

Can you find a flaw in this statement?

There’s a girl who has a large family. She has an equal amount of brothers and sisters, but each brother only has half as many brothers and sisters. What’s the correct amount of brothers and sisters?