What brings you down but never up?

What runs around the whole yard without moving?

Take 9 from 6, 10 from 9, 50 from 40, and leave 6.

How Come ??

A swan sits at the center of a perfectly circular lake. At an edge of the lake stands a ravenous monster waiting to devour the swan. The monster can not enter the water, but it will run around the circumference of the lake to try to catch the swan as soon as it reaches the shore. The monster moves at 4 times the speed of the swan, and it will always move in the direction along the shore that brings it closer to the swan the quickest. Both the swan and the the monster can change directions in an instant.
The swan knows that if it can reach the lake's shore without the monster right on top of it, it can instantly escape into the surrounding forest.

How can the swan successfully escape?

Today, I celebrated my 32nd birthday but I was born in 1972.
How is this possible?

What do you think with the below Picture ?

Here is a mathematical expression that also secretly tells a movie name. What movie is that?

I am the beginning of everything, the end of everywhere. I'm the beginning of eternity, the end of time and space. What am I?

A tourist visits a small town for his research. While in the town, he decides to get a haircut. Since the town is quite small, there are only two barbers in the town � one on the North Street and one on the South Street. The barbershop on the North Street is a mess and the barber has a weird and pathetic haircut. While the barbershop at the South Street is pretty tidy and the barber as well has an impressive haircut.

Which barbershop will the tourist visit for his haircut and why?

How is a fly different from a mosquito?