What has 13 hearts but no other organs?

How many words can a pen with half refill write?

What word is pronounced the same if you take away four of its five letters?

We have shown you a regular water barrel as below. Without using any measuring device can you check if the barrel is more than half-filled or less than half-filled?

What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see? What is it?

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 not alive, but I grow; I don't have lungs, but I need air; I don't have a mouth, but water kills me. What am I?

You bought me for dinner but never eat me. What am I?

What number should come in place of the question mark below?

A frog is at the bottom of a 30-meter well. Each day he summons enough energy for one 3-meter leap up the well. Exhausted, he then hangs there for the rest of the day. At night, while he is asleep, he slips 2 meters backwards. How many days does it take him to escape from the well?