Can you convert the number zero(0) into a positive number using just one mathematical operator ?

I can sizzle like bacon,
I am made with an egg,
I have plenty of backbone, but lack a good leg,
I peel layers like onions, but still remain whole,
I can be long, like a flagpole, yet fit in a hole.

It's pretty hard to give up.
If you remove a part of it, you will be left with a bit.
Even if you remove another part, the bit still remains.
Remove one more and it still remains.

What is it?

What number does the below three word/phrase identify and why?
1. Deck
2. Year
3. Singing in the Rain

I have branches, but no fruit, trunk or leaves. What am I?

I travel all around the world but always stay in the corner. What am I?

The person who makes it has no need for it. He who purchases it does not use it. The person who does use it does not know they are. What is it?

Can it be possible to build a house that has all its four walls facing towards the South?

It walks on 4 when its young, walks on 2 when it's older, and walks on 3 when its very old?

How do you go from 98 to 720 using just one letter?