It walks on 4 when its young, walks on 2 when it's older, and walks on 3 when its very old?

Can you count the number of triangles in the given picture?

Using Only Five 5's and any mathematical operator make sum as 37

Identify the 10 differences between the two given pictures.

If an electric train is travelling south, then which way is the smoke going?

What is so fragile that saying its name breaks it?

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

Can you find out which number multiplied by itself will give the output as 12345678987654321?

How do you go from 98 to 720 using just one letter?

Queen Elizabeth organised a royal party.

To Avoid uninvited guest royal family set a password.
Jack (an uninvited person) plan to enter the party. He stand nearby the door.

First guest comes, the security person said 'twelve' and guest replied with six.
Second guest comes , the security person said 'six' and guest replied with 'three'.

Jack thought is enough and he walked to the entry point. The security person said 'eight' , Jack replied smilingly 'four'.
He was immediately thrown out of the party. why ?