Why is the Hole below a Lock?

How many times do a clock's hands overlap in a day ?

In the picture, you can see a chess board. On the top left position, the K marks a knight. Now, can you move the knight in a manner that after 63 moves, the knight has been placed at all the squares exactly once excluding the starting square?

Place the numbers from 1 to 9 in the circles in a manner that each side of the triangle sums up to 17.

Many have heard it, but nobody has ever seen it, and it will not speak back until spoken to. What is it?

In the addition below, all digits have been replaced by letters. Equal letters represent equal digits and different letters represent different digits.
ABCABA
BBDCAA
ABEABB
ABDBAA
------- +
AAFGBDH
What does the complete addition look like in digits?

Twice ten are six of us,

Six are but three of us,

Nine are but four of us;

What can we possibly be?

Would you know more of us?

Twelve are but six of us,

Five are but four, do you see?

What are we?

Can you find the dog hidden in a group of pandas?

Find three whole, positive numbers that have the same answer when multiplied together as when added together.

First, think of the colour of clouds. Next think the colour of snow. Last, think of the colour of the moon. Now, what do cows drink?