What always comes into a house through the keyhole?

My friends called me Iron59 because my parents are a chemist and a mathematician. What is my real name?

There was a minor accident with a doctor's son but the doctor noticed no major injury. After the treatment, the father of that doctors son is sitting with the son of the doctor without the doctor being in the room.

How can this be possible?

Our product and our sum always give the same answer. Who are we?

I’m tall when I’m young, and I’m short when I’m old. What am I?

How can you make a TV, a bed, a dog, and a car liquid?

Rearrange the letters in "new door" to make one word.

Count the number of triangles in the given picture.

Can you find out the number that should replace the question mark with a valid reason?

If all Goats are Sheep and all Sheep are Deers, are all Deers Goats ?