An infinite number of mathematicians are standing behind a bar. The first asks the barman for half a pint of beer, the second for a quarter pint, the third an eighth, and so on. How many pints of beer will the barman need to fulfill all mathematicians' wishes?

There were two grandmothers and their two granddaughters.
There were two husbands and their two wives.
There were two fathers and their two daughters.
There were two mothers and their two sons.
There were two maidens and their two mothers.
There were two sisters and their two brothers.
Yet there are only six, who are buried here,
All are born legitimate and relationships clear.
How can this happen?

How many pluses should we put between the digits of 987654321 to get a total of 99, and where?

A certain street contains 100 buildings. They are numbered from 1 to 100. How many 9's are used in these numbers?

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
=========

Can you write down eight eights so that they add up to one thousand?

There was an aeroplane crash, every single person died, but two people survived. How is this possible?

What is common among 11, 69, and 88?

A King wants to send the diamond ring to his girlfriend securely. He got multiple locks and their corresponding keys. His girlfriend does not have any keys to these locks and if he sends the key without a lock, the key can be copied in the way. How can King send the ring to his girlfriend securely?

Can you find the odd number in the following?

2716, 4135, 5321 and 7145