Replace the question mark with the number below given a simple math problem.

Can you count the number of seconds in a year?

Clue: You need to bother about calculation.

If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?

Find the value of "a" by solving the maths equation in the picture below:

Prove that twice of ten is the same as twice of eleven.

You see a boat filled with people, yet there isn’t a single person on board. How is that possible?

What is the centre of gravity?

I have no life, but I can die. What am I?

If Japan and Panama decided to merge into a single country, probably people will name it Japanama.

Can you think of two more such country's unions that could produce similar names like Japanama by overlapping their three letters?

I am a five-letter word under you,
Remove the first letter and I am above you,
Remove the second as well and I am around you.

Who am I?