Use only one mathematical symbol and all numbers (0-9) to get a sum of 99

It can't be seen, can't be felt, can't be heard, and can't be smelt.
It lies behind stars and under hills, And empty holes it fills.
It comes first and follows after, Ends life, and kills laughter.
What is it?

I know there are two methods by using three time the same number with a plus(+) operator , you can make sum as 60.

One of them is 20+20+20.

whats the other way ?

What is in seasons, seconds, centuries and minutes but not in decades, years or days?

A large container is kept in open under the rain. Every passing hour, the water collected inside the container becomes double what it was.

In ten hours, the container is filled completely. Can you calculate how long would it have taken to be filled in half?

What does the below image rebus riddle means ?

You see a mathematical expression in the picture. Can you think of a movie that this expression refers to?

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

A generous owner of a company decided to give a bonus of $45 to every man and $60 to every woman on his birthday. But only one-ninth of the men and one-twelfth of the women were present to take the bonus.

Can you calculate the amount of money the owner spent if there were 3552 employees?

Which five letter word can be added at the end of below word to form a
valid word?

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