What is the fewest number of coins that would be required in order to make sure each and every coin touches exactly three other coins?

Identify the 10 differences between the two given pictures.

There once were seven dwarfs who were all brothers. They were all born two years apart. The youngest dwarf is seven years old. How old is his oldest brother?

There is a place where if I stand up straight, I will still be considered sideways.

It spends most of its day eating white, but when it’s quick enough, it gets to eat fruit and sometimes some blue things. It’s in a dark room, where the walls are blue, it runs from a ghost that roams the halls and haunts it all the time. What is it?

If nine thousand, nine hundred nine dollars is written as $9,909,
how should twelve thousand, twelve hundred twelve dollars be written?

What English word has three consecutive double letters?

What is the four-digit number in which the first digit is one-third the second, the third is the sum of the first two, and the last is three times the second?

Can you find out the remainder when 3^300 is divided by 5?

Which tank will fill first?