Why do people go to bed?

Until it is measured, not known. Yet how you miss it when it has gone. What is it?

What does this simple rebus mean?

Can you find the largest Three-digit number whose sum is 14 and whose square is less than 5,00,000?

What number does the below three word/phrase identify and why?
1. Deck
2. Year
3. Singing in the Rain

Can you find a seven digit number which describes itself. The first digit is the number of zeros in the number. The second digit is the number of ones in the number, etc. For example, in the number 21200, there are 2 zeros, 1 one, 2 twos, 0 threes and 0 fours.

You are playing as white and given four rooks to checkmate the black king in four moves with the following rules 1. You can place one rook every move and ensure the black king should be in check position.2. After four moves the black king should be in the checkmate position.

Count the number of squares in the picture below.

Steffi's daughter Jazelle needs to be picked up from school every day.
Steffi asks one of her colleagues to pick up Jazelle from the school. Steffi devised a password system to confirm that Jazelle goes with the correct colleague only.

The password on Monday was SJM16.
The password on Wednesday was TAW39.

What will the password be for Friday?

What can you see in the middle of March and April that you can never see in any other month?