Can you replace the question mark with the correct number?

I am a three digit number.
My tens digit is five more than my ones digit.
My hundreds digit is eight less than my tens digit.
What number am I?

What is the relationship between these matchstick pictures below?

A word I know,
Six letters contain,
Subtract just one,
And twelve is what remains.

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?

If I remove one from eleven it becomes Ten and if I remove one from nine also becomes Ten. How?

A Doctor always sneezes before the rain. Doctor sneezes, Will it rain?

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

Before Mount Everest was discovered, what was the highest mountain in the world?

John asked Jack, "The time right now is 7 pm. Can you tell me what will be the time 23, 999, 995 hours later ?"

While Bella does not know the answer, do you ?