What does this rebus puzzle means ?

When I got four, I have it none.
When I got two, I have it some.
When I got none, I have it all.

What is it?

What time is it when an elephant sits on a fence?

You have a roll of cloth 1km long. You have a machine which cuts this roll into pieces of 10-meter-long cloth.

How long would it take for the machine to cut the roll if each cut took 4 secs?

What has 88 keys?

My friends called me Iron59 because my parents are a chemist and a mathematician. What is my real name?

What is the difference between a jeweller and a jailer?

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

What makes this number unique: 8,549,176,320?

Find the number of squares in the below-given picture.