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

I am a word that begins with the letter “i.” If you add the letter “a” to me, I become a new word with a different meaning, but that sounds exactly the same. What word am I?

If eleven plus two equals one, what does nine plus five equal?

There is one thing that goes round the house and also inside the house but never even share a brief touch. What is it?

What word is pronounced the same if you take away four of its five letters?

Solve below popular number sequence
314 159 265 358 979 323 846 ?

Below toothpicks/matchsticks indicate the group of fishes moving from west to east direction. Can you make them move from east to west by just moving three toothpicks/matchsticks?

I get hot but I never sweat,
I cook food but I am not a chef,
I have a door but you can't enter me,
I have a light but I am not a lamp.
Who am I?

What is the below Rebus indicate?

How many times in a given day, minutes and hour clock comes in a straight line ?