What has to be broken before you can use it?

Can you find the key in the picture below?

Can you divide numbers from 1 to 9 (1 2 3 4 5 6 7 8 9) into two groups so that the sum of the numbers of each group is equal?

Note: 9 cannot be turned over to make it 6.

A new Engineering building containing 100 offices had just been completed. John was hired to paint the numbers 1 to 100 on the doors. How many times will John have to paint the number nine (9)?

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

John left on a horse on Thursday , was gone for two days, and came back on Thursday after completing his work. How did that happen?

When I asked a girl's name she told me her name is the date '07/09/2001'.

I thought for a few seconds and then I got her name. Do you?

A girl was sitting in her hotel room when she heard a knock on the door. She opened the door and found that a man was standing outside.
The man said, "Oh! I am really sorry, I thought this was my room."
He then walked through the corridor to the elevator. The girl did not know the man. She closed her door and called security asking them to apprehend the man.
What made her suspicious of that man? He might have been genuinely mistaken.

What 4-letter word can be written forward, backward or upside down, and can still be read from left to right?

I have teeth but i don't bite. Who Am I ?