It walks on 4 when its young, walks on 2 when it's older, and walks on 3 when its very old?

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.

Find the Next Number in the Sequence

2 9 3 1 8 4 3 6 5 7 ?

What Time Should the last watch show in the below figure?

81 x 9 = 801. What must you do to make the this equation true?

Create a number using only the digits 4,4,3,3,2,2,1 and 1. So i can only be eight digits. You have to make sure the ones are separated by one digit, the twos are separated by two digits the threes are separated with three digits and the fours are separated by four digits

What is so fragile that saying its name breaks it?

If,
9 * 8 * 7 = 65
8 * 7 * 6 = 50
7 * 6 * 5 = 37

Find
6 * 5 * 4 = ?

What can go up a chimney down, but can’t go down a chimney up?

What does this rebus riddle means ?