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

If nine thousand, nine hundred nine dollars is written as $9,909,
how should twelve thousand, twelve hundred twelve dollars be written?

In the Chess Board picture below white army is arranged. You need to add a black army on the board such that no piece is under any threat.
Note: Army comprised of 1 king, 1 queen, 2 rooks, 2 bishops, 2 knights, and 8 pawns.

You walk into a room that contains a match, a kerosene lamp, a candle and a fireplace. What would you light first?

He digs out tiny caves and stores gold and silver in them. He also built bridges of silver and made crowns of gold. They are the smallest you could imagine. Sooner or later everybody needs his help, yet many people are afraid to let him help them. Who is he?

Solve below rebus puzzle?

John: "Hi Teacher, What is your favourite movie ?".
Chemistry Teacher: "Indium Cerium Platinum Iodine Oxygen Nitrogen".
Ten seconds later... John replied I got it.

Do you?

Quickly Solve this riddle

7 - 4 + 3 * 0 + 1 = ?

A bomb goes off.
Carnage.
One person, only a few feet away, survives! How can this be?

You can see it everyday, But cannot touch it at will. What is it?