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

Nine marbles are arranged in the image below. Can you slide two marbles to form a square?

On a certain island, people are gifted with assorted eye colours. There are a hundred green-coloured and a hundred grey-coloured pairs of eyes. On that island, there is no mirror available. Thus no one knows the eye color of their own. They could have asked each other but that is prohibited. They are not allowed to converse with each other. However, they can study and analyze other's eyes. They don't even know the statistics so it is believable to them that their eyes can be blue as well. There is a chance of freedom from the island. If anyone can guess the colour of his own eyes correctly, he will be set free and can leave the island.

On one particular day, an outsider comes to the island and announces that he has seen someone with grey colour eyes. What will happen now?

If eleven plus two equals one, what does nine plus five equal?

My thunder comes before lightning.
My lightning comes before my rain.
My rain dries up all the land it touches.

Who am I?

There is so small cabin inside a deep forest.
All the forest burned out to worst possible but the inside of the cabin is still the same.
However all the person inside the cabin die.

How come ?

Can you find the next number in the below sequence
3 , 7 , 10 , 11 , 12 , 17 ?

Keyboard words are not in alphabetical order, Why?

John is asked to stand behind Jacob and Jacob is asked to stand behind John. Both of them feel confused about it and don't know what to do?

But it is quite possible, do you know how?

Use only one mathematical symbol and all numbers (0-9) to get a sum of 99