What does this rebus puzzle means ?

What number divided by 4 is the same as that number minus 4?

Which word does the below Plexor means ?

What you cannot hold but it is yours?

In the image given, you can find several triangles. Can you count them all?

A word I know,
Six letters contain,
Subtract just one,
And twelve is what remains.

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

What has a ring but no finger?

A man fell off a smuggling boat into deep water. He could not swim and he was not wearing anything to keep him afloat. It took 30 minutes for the people on the boat to realize someone was missing. The missing man was rescued two hours later on the return trip. Why didn't he drown? Note:- He didn't know swimming, the sea was deep, and He wasn't holding anything

I inserted a coin in a bottle and closed its mouth with the help of a cork. Now, I was able to take the coin out from the bottle without taking out the cork or breaking the bottle. Can you tell me how I did it?