What number when divided in half becomes zero?

What is the riddle which can be asked all day with a different correct answer each time.

In a mathematical quiz, you are asked the following question:

Use three 9s in a mathematical expression without dividing or multiplying to form the number one.

Can you answer the question?

I have a big mouth and I am also quite loud! I am NOT a gossip but I do get involved with everyone's dirty business.

A bomb goes off.
Carnage.
One person, only a few feet away, survives! How can this be?

Baseball bat and ball cost $100. If the bat cost $99 more than the ball, what is the cost of each?

That attorney is my brother, testified the accountant.

But the attorney testified he didn't have a brother.

Who is lying?

A shopkeeper allows people to buy a cold drink bottle in exchange for five empty bottles. A guy had a party at home and spent 77 cold drink bottles at the party. Now he has 77 empty bottles with him.

How many bottles do you think he can buy in exchange for those 77 empty bottles?

Replace the question mark with the correct number.

2 + 2= 4
3 + 3= 18
4 + 4= 48
5 + 5= ?

I have one of the three numbers: 1, 2, or 3 in my mind. I speak only truth. You can ask me just one question for which I will only reply in yes or no or don't know. What question will you ask from me so that you are able to know the number?