I travel all around the world but always stay in the corner. What am I?

Move four matchsticks to the below square to form three squares?

John was visiting his friend Jacob. He found out that his friend's wife had just killed a burglar in self-defense.
John asks Jacob about what happened and he told that "His wife was watching television when suddenly the bell rang. She thought that it is her husband Jacob but she found the burglar who attacked her instantly and she got so frightened that she killed the burglar immediately with the knife.
John asked the police to arrest his friend's wife. Why?

I sleep during the day and fly at night, but I have no feathers to aid my flight. What am I?

You measure my life in hours
I serve you by expiring
I vanish faster when I am thin
and slower when I am thick
The wind is my energy
What am I?

You and your two friends are working in a multinational company. How can you three find out the average salary of you all without disclosing your own salary to the other two?

A monk has a very specific ritual for climbing up the steps to the temple. First, he climbs up to the middle step and meditates for 1 minute. Then he climbs up 8 steps and faces east until he hears a bird singing. Then he walks down 12 steps and picks up a pebble. He takes one step up and tosses the pebble over his left shoulder. Now, he walks up the remaining steps three at a time which only takes him 9 paces. How many steps are there?

The product of three consecutive numbers is 7980.
Then the sum of these consecutive numbers would be?

What mathematical symbol can be put between 5 and 9, to get a number bigger than 5 and smaller than 9?

In 1990, a person is 15 years old. In 1995, that same person is 10 years old. How can this be?