What does below rebus means ?

Take away my first letter, then take away my second letter. Then take away the rest of my letters, yet I remain the same. What am I?

Prove that twice of ten is the same as twice of eleven.

What can go up a chimney down, but can’t go down a chimney up?

What number when divided in half becomes zero?

What's the only room from which no one can enter or leave

The peacock is a bird that does not lay eggs. How do they get baby peacocks?

If it took eight men ten hours to build a wall, how long would it take four men to build it?

Why is it very easy to weigh a fish?

What seven-letter word has hundreds of letters in it?