When I get multiplied by any number, the sum of the figures in the product is always me. What am I?

Which famous Hollywood movie name is hidden in the below rebus?

A shepherd had 18 sheep, out of which, all but ten died.

Can you tell us how many sheep was he left with?

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?

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

Can you find out the remainder when 3^300 is divided by 5?

What is the word or phrase?

How can you write nineteen in a manner that if we take out one, it becomes twenty?

I am an eight letter word and I am a computer terminology.
The second, third and fourth letters make an animal.
The fourth, fifth, sixth, seventh and eighth letters make a weapon.
The first, second, third and fourth letters can be taken as an outcome of any exam.
The fifth, sixth, seventh and eighth letter combine to form a high end typing software.

Can you tell who am I ?

You bought me for dinner but never eat me. What am I?