If I remove one from eleven it becomes Ten and if I remove one from nine also becomes Ten. How?

I have four wings but can't fly.
I express no emotions.
I am found on the exact spot every time you look.
I keep toiling away with a little sound.

Do you know what am I?

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

John was piloting a plane behind a car but was never able to overtake it. Why?

Twenty frogs are sitting on a log floating on the surface of a river. Two of them decide to jump off into the water.

How many frogs are there on the log at this moment?

You enter your friend's room. He is not in his room. Although you see that on the bed there are two dogs, five cats, two giraffes and three pigs. Also, a couple of chickens and ducks are flying in the room.

Calculate the number of legs standing on the floor.

I have a hole in my back and legs I lack.
I live where I can’t breathe and I eat without teeth.
What am I?

I am the beginning of the end, and the end of time and space. I am essential to creation, and I surround every place. What am I?

I am taken from a mine and shut up in a wooden case, from which I am never released, and yet I am used by almost every person. What am I?

I am looking for a word that change both gender and number when i add the letter 'S'.

What Word am I Looking For ?