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

which number am I?

What is next number in the pattern below:

131 517 192 123 ?

Can you arrange four 9's and use at most 2 math symbols, to make the total 100?

Joseph buys three kinds of chocolates for 100 rupees. The first one is priced at 5 rupees, second one at 3 rupees and third one at 0.5 rupees.

If he bought 100 chocolates in total, how many pieces do you think he bought each chocolate?

I throw two dice simultaneously.

What is the probability of getting a sum as 9 of the two numbers shown?

In case you were starting to feel confident, this one was meant for third graders in Vietnam. The answer is 66, but we don't blame you for scratching your head about how they got there.

Can you think of any three-dimensional shape that comprises of exactly two surfaces?

A tree doubled in height each year until it reached its maximum height over the course of ten years. How many years did it take for the tree to reach half its maximum height?

In a stable, there are men and horses. In all, there are 22 heads and 72 feet. How many men and how many horses are in the stable

My grandson is about as many days as my son in weeks, and my grandson is as many months as I am in years. My grandson, my son and I together are 120 years. Can you tell me my age in years ?