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?

Can you discover the missing number in this series?

37, 10, 82
29, 11, 47
96, 15, 87
42, ?, 15

You have three orange, two pink and five purple balls in the drawer beside your bed. There is no electricity and the room is entirely dark. How many balls must you take out to ensure at least one ball of each colour at least?

Prove that twice of ten is the same as twice of eleven.

John: "Hi Teacher, What is your favourite movie ?".
Chemistry Teacher: "Indium Cerium Platinum Iodine Oxygen Nitrogen".
Ten seconds later... John replied I got it.

Do you?

What Deficiency does the below rebus represent?

VIT_MIN

How is the moon similar to a dollar?

The square root of number 121 is "11". What is the square root of the number "12345678987654321."?

You have two buckets of 11 liters and 6 litres.
How can you measure exactly 8 litres?

Where do fish keep their money?