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.

I am first found in caves, now prolific online; I am a depiction, a drawing, a symbol, or sign. I will convey whichever mood you could wish; or for that matter, a fist, flask, or fish. What am I?

Find the missing number in the sequence below:

How is the moon similar to a dollar?

Can you convert the number zero(0) into a positive number using just one mathematical operator ?

By removing one matchstick and adding one matchstick, can you convert the word "ZOO" to an animal name?

Can you find the key in the picture below?

What is harder to catch the faster you run?

Can you find the hidden animal in the picture below?

In a science lab, a petri dish hosts a healthy colony of yeast for an experiment. Now every minute, all the yeast cells divide into two. At noon, there was just a single cell of yeast and at 1:22, the Petri dish was half full. Can you calculate when the dish will be full of yeast?