What does this mathematical rebus means ?

Always in you, Sometimes on you;

If I surround you, I can kill you.

What am I?

I don't get anymore wetter, no matter how much rain falls on me.

The product of three consecutive numbers is 7980.
Then the sum of these consecutive numbers would be?

Which tank will fill first?

How can one talk without saying a single word?

Can you find a number that lies one third of the distance between 1/3 and 2/3?

Chocolate costs 6 rupees and a Toy costs 5 rupees. If you have 32 rupees in total, how many chocolates and how many Toys can be purchased with that amount?

In one of the popular batman series movie "Batman Forever", there was a riddle that goes like "Tear me off and then scratch my head and I was red then and now I am back. Who am I?

A plane crashed between the border of Mexico and America. Where do you bury the survivors?