Can You Solve This Card Master Puzzle?

Get out your deck of cards!

This puzzle requires you to think logically. You can’t remove your blindfold or damage the cards, but you can count them by feel.

You have to divide the cards into two piles, but the piles don’t have to be the same size. Start by randomly making one pile of 10 and one pile of 42. Here are the possible combinations of cards turned face up in each pile, starting with the pile of 10.

0 and 10

1 and 9

2 and 8

3 and 7

4 and 6

5 and 5

6 and 4

7 and 3

8 and 2

9 and 1

10 and 0

We’ll pretend that you ended up with 7 cards face up in the first (smaller) pile and 3 face up in the second (larger) pile.

Notice that in each case, the two numbers add up to 10. This makes sense since you started with 10 cards face up.

SEE ALSO: Think Outside the Box to Find the Next Number in This Sequence

Since you know that the first pile has 10 cards in it, you can flip the entire pile over and know how many cards would now be face up. If we look at the number of face-up cards in each pile again, we get:

0 –> 10 and 10

1 –> 9 and 9

2 –> 8 and 8

3 –> 7 and 7

4 –> 6 and 6

5 –> 5 and 5

6 –> 4 and 4

7 –> 3 and 3

8 –> 2 and 2

9 –> 1 and 1

10 –> 0 and 0

In our case where you started with 7 cards facing up in the 10 pile and 3 cards facing up in the 42 pile, you now have 3 cards facing up in each pile.

This works for any combination. You will have a pile of 10 cards and a pile of 42 cards with the same number of cards facing up in each pile! There may be more or fewer than 10 cards facing up in total at this point, but keeping that number constant was never part of the rules. Remove your blindfold and give yourself a round of applause!

Try this puzzle next: Matchstick Brain Teaser