What does this mathematical rebus means ?

To attend world science seminar, A famous chemist from Mexico visit
London. In the lab, the scientist was killed and his six assistants were under suspicion of killing the chemist.
Name of six assistants: Austin, Wayne, Dege, Oscaru, Lingard, and Rojo.
He left a note "76-20-44 79-16-22-7"

A local detective Jack was called to solve the case,

After reading the note, Jack instantly asked the police to arrest the murderers.

Who are the murderers?

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

In the picture that is attached with this question, you can find a square which comprises of four little squares inside it. Consider this square to be made with matchsticks. You have to remove two matchsticks such that only two squares remain instead of five.How will you do it ?

When monkey rotate the gear, which mark will be hit 1 or 2 ?

You need to move three matchsticks to form three squares. Can you do it?

Which alphabet is a part of our body?

John killed hundreds of people mercilessly and yet the police were not able to put her behind the bars. Why?

I never was there, I am always to be.
You have never ever seen me, not ever you will.
Yet I am the confidence of everyone.

Who Am I?

Our product and our sum always give the same answer. Who are we?