Can you circle exactly four of these numbers such that the total is twelve?

1 6 1
6 1 6
1 6 1
6 1 6

When I asked a girl's name she told me her name is the date '07/09/2001'.

I thought for a few seconds and then I got her name. Do you?

You are in a room with no metal objects except for two iron rods. Only one of them is a magnet.
How can you identify which one is a magnet?

John and Jill are madly in love with each other. To remind Jill of his pure love, John wants to send her a ring by post but in their country where burglary is quite prominent, any package that is not locked comes under the risk of being stolen for the contents.

John and Jill possess many padlocks but neither one of them has the other key.

Can you find a way John can send the ring to Jill safely?

Can you replace the question mark with the correct number?

Move three sticks of the spiral below to form a square.

I have no life, but I can die. What am I?

Using Only Five 5's and any mathematical operator make sum as 37

If you remove one from eleven, it becomes ten. If you remove one from nine, it becomes ten.

How is this possible?

What has many teeth, but cannot bite?