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

What occurs twice in a week, once in a year but never in a day?

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

Solve the alphametic puzzle by replacing the alphabet with the number.

S T O R M +
S O L E S
=========
T O W E L
=========

Replace the question mark with the correct number.

Out of three Friends John, Jacob and Jonny one of them is a king, one is a bureaucrat, and one is a Spy.

The king always tells the truth, the bureaucrat always lies, and the Spy can either lie or tell the truth.

John says: Jonny is a bureaucrat
Jacob says: John is a king
Jonny says: I am a Spy

Tell me, Who is the king, who is the bureaucrat, and who is the Spy?

On her drawing table, Sayna lit 12 coloured candles. A few seconds later she blew two candles off.

How many candles Sayna have at the end?

Take 9 from 6, 10 from 9, 50 from 40, and leave 6.

How Come ??

Below the four parts have been reorganised. The four partitions are exactly the same in both arrangements. Why is there a hole?

A man dies of old age on his 25 birthday. How is this possible?