What do you get if you add 2 to 100 four times?

A man was gazing through the window of the 23rd floor of the building. He suddenly opened the window and jumped on the other side of the window. On landing on the floor, there was not a sheer mark of injury on him.

How can that be possible if he did not use any kind of parachute and did not land on a soft surface?

I cannot talk, but I always reply when spoken to. What am I?

I am a prime number.
The double of myself is equal to the square of me.

which number am I?

Known by all without exception, Forever here, for your protection, Sometimes strong, sometimes weak, Right after the night I come - hot and chic. And while millions of miles away, I always get to you, I find my way. No life around could do without me, Can you guess what I might be?

Sherlock Holmes was challenged to make a pre-drawn line smaller without erasing it. He did it in fractions of seconds. How?

Prove that twice of ten is the same as twice of eleven.

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?

using four eights (8) and a one (1) and one mathematical symbol , create the number 100

What Adam and Eve do not have but the rest of the people have?