Which number should replace the question mark?

John has eleven friends. He has a bowl containing eleven apples. Now He wants to divide the eleven apples among his friends, in such a way that an apple should remain in his bowl.
How can He do it?

My cousin lives in one story house in Antarctica. His house is made the of-of sandstone. what is the color of stairs?

How many pluses should we put between the digits of 987654321 to get a total of 99, and where?

Can you Find and name the hidden bird in the picture below ?

John can fit six large chocolate boxes or nine small chocolate boxes into a carton. How many cartons will he require to put sixty-six chocolate boxes into?

What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see?

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

Can you identify the hidden rebus in the image below?

While house hunting in London, I came across a very good leasehold property Discussing the lease the landlady told me:

'The property was originally on a 99 years lease and two-thirds of the time passed is equal to four-fifths of the time to come. Now work it out for yourself and see how many years are to go!