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

Take one out and scratch my head, I am now black but once was red. What am I?

Why is 6 afraid of 7?

The more it dries, the wetter it becomes. Can you tell what it is?

In the given picture, you can find a square in the centre and four open squares. Can you form three closed squares by just moving three sticks from their positions respectively?

It's a 7-letter word.
If we remove 1 letter from it, it remains the same.
If we remove 2 letters from it, it remains the same.
If we remove 3 letters from it, it remains the same.
If we remove all the letters from it, still it remains the same.
What is it?

Here is a Swiss Cross. You have to make two straight cuts in the figure so that it is divided into four congruent pieces. Also, you should be able to join these pieces into a square then. Can you accept this challenge?

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

What can you catch but never throw?

I have lakes with no water, mountains with no stone and cities with no buildings. What am I?