I am a prime number.
The double of myself is equal to the square of me.

which number am I?

How many people must be gathered together in a room, before you can be certain that there is a greater than 50/50 chance that at least two of them have the same birthday?

You need to arrange three 7 and mathematical symbols to form number 1?

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

There are two candles. Both will only burn exactly for an hour. How will you use these two candles to measure forty-five minutes?

There is a number which when you multiply by 3 and subtract 2 from the result, then the resulting number is the reverse of the actual number.

What is the smallest number that stands true on the statement?

Find the value of "?" in the ball picture Riddle below:

Use the numbers 2, 3, 4 and 5 and the symbols + and = to make a true equation. Conditions: Each must be used exactly once and no other numbers or symbols can be used.

A chicken farmer has figured out that a hen and a half can lay an egg and a half in a day and a half. How many hens does the farmer need to produce one dozen eggs in six days?

Find three whole, positive numbers that have the same answer when multiplied together as when added together.