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

Living above a star, I do not burn
Eleven friends and they do not turn
I can just be visited in a sequence, not once or repeatedly
PQRS are my initials
Can you tell my name accurately?

A certain street contains 100 buildings. They are numbered from 1 to 100. How many 9's are used in these numbers?

Until it is measured, not known. Yet how you miss it when it has gone. What is it?

What has hands, but can’t clap?

Can you name three consecutive days without using the words Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, or Sunday?

Do you know of a place where the wind blows south and then suddenly shifts direction towards the north?

What does below chemistry rebus means?

In a competitive exam, each correct answer could win you 10 points and each wrong answer could lose you 5 points. You sat in the exam and answered all the 20 questions, which were given in the exam.
When you checked the result, you scored 125 marks on the test.

Can you calculate how many answers given by you were wrong?

Can you arrange four 9's and use at most 2 math symbols, to make the total 100?