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

which number am I?

What three numbers, none of which is zero, give the same result whether they’re added or multiplied?

Find three numbers such that When we multiply three numbers, we will get the prime numbers. The difference between the second and the first number is equal to the third and second.

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

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

If "P" means "-", "Q" means "/", "R" means "+", and "S" means "*" then find the value of the following:

21 Q 7 R 9 S 10 P 13

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?

Double it and multiply it by 4. Then divide it by 8 and you’ll have it once more. What number is it?

What number divided by 4 is the same as that number minus 4?

What's a single-digit number with no value?