Find the number of squares in the below picture

What can you hold in your right hand, but never in your left hand?

Replace the question mark with the number below given a simple math problem.

Why is a river so rich ?

The answer I give is yes, but what I mean is no. What was the question?

A blonde put eyeliner on her head. Why?

Can you find out a way through which you can make five squares out of the given figure by moving just six match sticks?

I am five letter word that is under you.
If you remove my 1st letter, then I am over you.
If you remove my 1st and 2nd letters then I am all around you.

Who am I?

Sherlock breaks into a crime scene. The victim is the owner who is slumped dead on a chair and have a bullet hole in his head. A gun lies on the floor and a cassette recorder is found on the table. On pressing the play button, Sherlock hears the message 'I have committed sins in my life and now I offer my soul to the great Lord' and followed a gunshot Sherlock smiles and informed the police that's its a murder.

Why did he think so?

I am white when I am dirty, and black when I am clean. What am I?