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

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

Christina is older than Kareena and Karishma. Katrina is older than Karishma and younger than Kareena. If Kareena has a brother named John, who is older than Christina, who's the youngest?

What comes
Once in a Year
Twice in a Month
4 times in a Week
6 times in a Day

What is black when you buy it, red when you use it, and gray when you throw it away?

What word is pronounced the same if you take away four of its five letters?

A man hijacks an aeroplane transporting both passengers(8 of them) and valuable cargo. After taking the cargo, the man demands nine parachutes, puts one of them on, and jumps, leaving the other eight behind. Why did he want eight?

What Does this text mean:

important=important

You can find some missing letters in the picture. By placing two particular letters in the spaces, you can form a nine lettered word beginning from one of the corners and going clockwise direction to the middle. Can you find out the letters and the word?

Name one eight-letter word with 'kst' in the middle, 'in' the beginning, 'and' at the end.?