Replace the question mark with the correct number.

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

_ _ _ IE _ _
_ _ _ IE _
_ _ IE _ _
_ _ IE _
_ _ _ _ IE

Like you see, some letters have gone missing from these words that contain the IE pair at some or the other place. The letters that will be used to fill the blanks are given below. Use them and form meaningful words. Can you do that?

A, C, D, F, H, K, L, M, N, N, O, R, R, S, S, S, T, T, Y and Y.

We have shown you a regular water barrel as below. Without using any measuring device can you check if the barrel is more than half-filled or less than half-filled?

Complete the series by replacing "?" with the correct number.

ST ND RD TH '?'

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

Count the number of lines in the image below ?

How can one talk without saying a single word?

1 + 9 + 8 = ?
considering, 28 + 8 + 92 = 10

People make me, save me, change me, raise me. What am I?