Using eight eights and addition only, can you make 1000?

A brand new Mobile Phone was on sale at 20% as a promotional offer. By what per cent must the Mobile price be increased to sell it at the original price again?

Below the four parts have been reorganised. The four partitions are exactly the same in both arrangements. Why is there a hole?

Next Number in the Series,

5, 16, 49, 104, ?

I am written with two letters.
I said with the one.
I usually am seen with the two.

Who am I?

Who is that with a neck and no head, two arms and no hands? What is it?

What is the fastest way to double your money?

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

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

Find the hidden tiger in the given optical illusion ?