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

There are forty elephants and they have forty-fore heads. How can this be possible?

A Doctor always sneezes before the rain. Doctor sneezes, Will it rain?

It can't be seen, can't be felt, can't be heard, and can't be smelt.
It lies behind stars and under hills, And empty holes it fills.
It comes first and follows after, Ends life, and kills laughter.
What is it?

Decode below three cipher riddles:

26 L of the A
7 D of the W
1000 Y in a M

Identify The phrase in the picture.

Can you complete the sequence?

192, 021, 222, 324, 252, 627, 2__, 9__?

Which letter of the alphabet has the most water?

What is the next number?

77, 49, 36, 18 ?

I am under you when I am whole.
I shift above you if you remove the first letter.
I come all around you if you remove the second as well.

Can you tell me who I am?