Riddles with a mathematical twist

Although not needing deep mathematical knowledge...

• A blindfolded man is handed a deck of 52 cards and told that exactly 10 of these cards are facing up. How can he divide the cards into two piles (possibly of different sizes) with each pile having the same number of cards facing up?

An old-fashioned implication one:

• Mrs Claus always sneezes just before it starts snowing. She just sneezed. “This means that it’s going to start snowing”, thinks Santa. Is he correct?

Robbed these from http://math.alamzy.com/wp-content/uploads/2012/10/Handbook.pdf