Teacher ask the student

'Why are you standing on that chair in music class ?'.

what did student replied ?

Take one out and scratch my head, I am now black but once was red. What am I?

Find a 9-digit number, which you will gradually round off starting with units, then tenth, hundred etc., until you get to the last numeral, which you do not round off. The rounding alternates (up, down, up ...). After rounding off 8 times, the final number is 500000000. The original number is commensurable by 6 and 7, all the numbers from 1 to 9 are used, and after rounding four times the sum of the not-rounded numerals equals 24.

A boy and a girl are sitting on the porch.
"I'm a boy," says the child with black hair.
"I'm a girl," says the child with red hair.
If at least one of them is lying, who is which?

If you're 8 feet away from a door and with each move you advance half the distance to the door. How many moves will it take to reach the door?

This puzzle is for Harry Potter fans. Do you know why Tom Riddle is called Lord Voldemort?

A four-digit number (not beginning with 0) can be represented by ABCD. There is one number such that ABCD=A^B*C^D, where A^B means A raised to the B power. Can you find it?

I am white when I am dirty, and black when I am clean. What am I?

Can you count the number of lines in the below picture?

What are the next two letters in the following series and why?
W A T N T L I T F S _ _

*Hint: Check Puzzle Title