Can you convert the number zero(0) into a positive number using just one mathematical operator ?

One fine day, an intellectual man came to the emperor's court with the aim of testing Birbal's wittiness. In order to do this, he challenged Birbal to answer his question and hence prove that he was as intelligent and witty as he was said to be.
He asked Birbal, Do you want me to ask one difficult question or a hundred easy ones?
Since both Akbar and Birbal had had a tough day and were eager to leave, Birbal hastily told the intellectual to ask him a single difficult question.
Intellectual: OK. Tell me what came first into the world, the egg or the chicken?
Of course, the chicken, Birbal replied with a smile.
This time with a note of victory in his voice, the intellectual asked Birbal, How will you demonstrate that?
What did Birbal say?

How many cubic feet of dirt are in a hole of one foot deep, three feet long, and two feet wide?

What is the centre of gravity?

What kind of band never plays music?

Solve the rebus riddle in the picture below.

I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?

'Ferrari driver' easily beats the 'force driver' in a two-car race. How did Indian newspapers truthfully report so to look as a 'force drive' had outdone the 'Ferrari driver'? Think!!!

The following question it puts forth you:

25 - 55 + (85 + 65) = ?

Then, you are told that even though you might think it's wrong, the correct answer is actually 5!

Whats your reaction to it? How can this be true?

Name one eight-letter word with 'kst' in the middle, 'in' the beginning, 'and' at the end.?