Below, you will find the mathematical proof that 10 equals 9.99999?. But is that possible or there is something wrong about it? Can you find the error?

x = 9.999999...
10x = 99.999999...
10x - x = 90
9x = 90
x = 10

What has hands, but can’t clap?

When I go in I might cause pain. I cause you to spit and ask you not to swallow. I can fill your hole. What am I?

Find the value of "?" in the ball picture Riddle below:

How many triangles can you count in the figure given?

It comprises roots which nobody sees,
Much taller than those trees,
Up and up it goes,
Still it never grows?

A four-digit number (not beginning with 0) can be represented by ABCD. There is one number such that ABCD=A^B*C^D, where A^B means A raised to the B power. Can you find it?

You have a three-gallon and a five-gallon measuring device. You wish to measure out four gallons.

Can you divide the below-given shape into four equal and identical pieces?

Identify the 10 differences between the two given pictures.