There are 2 sand hourglasses.

The small one can measure 5 hours and the large one can measure 7 hours.

How can we measure 16 hours with 2 sand hourglasses running together ?

This puzzle is for Harry Potter fans. Do you know why Tom Riddle is called Lord Voldemort?

The day before yesterday I was 25 and the next year I will be 28. This is true only one day in a year. What day is my birthday?

One is to three as three is to five and five is to four and four is the magic number.
What is the pattern?

By removing one matchstick and adding one matchstick, can you convert the word "ZOO" to an animal name?

In front of you, there are 9 coins. They all look absolutely identical, but one of the coins is fake. However, you know that the fake coin is lighter than the rest, and in front of you is a balance scale. What is the least number of weightings you can use to find the counterfeit coin?

What begins with T, ends with T, and has T in it?

Find the next number in the series.
1 10 24 43 67 ?

John can fit six large chocolate boxes or nine small chocolate boxes into a carton. How many cartons will he require to put sixty-six chocolate boxes into?

What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see?