Replace the question mark with the number below given a simple math problem.

Which number should replace the question mark?

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

One day, John and his friends were playing around. Jacob hit something with a Pin and it popped. John's dad came into the room that very moment, but he wasn't mad. In fact, he was smiling. What did Jacob hit?

John went to a parrot shop in Mexico, and the parrot owner told him that his parrot is so unique that he repeats everything he hears. John got excited and immediately bought the parrot. John went home and spoke many words, but the parrot does not repeat anything.
He went again to the parrot shop and complaint to the shopkeeper, but the shopkeeper never lied. Explain?

What goes up but never comes down?

There is a box full of marbles,
all but two are blue,
all but two are green,
and all but two are red.

How many marbles are in the box?

Find three whole, positive numbers that have the same answer when multiplied together as when added together.

Two in a corner, one in a room, zero in a house, but one in a shelter. What am I?

Can you spot the hidden girl in the picture below?