Natural in key signature

In musical notation, a natural sign (♮) is an accidental sign used to cancel a flat or sharp from either a preceding note or the key signature.

1. What does it mean when there are naturals in the key signature?
2. Can Naturals be present in a key signature?
3. What key has 4 Naturals?
4. How do you write a natural sign?

What does it mean when there are naturals in the key signature?

A natural sign looks like this:

It means that you play the pitch without modification. A key signature will only contain one kind of accidentals, either sharps or flats, but never both.

Can Naturals be present in a key signature?

Sometimes, the first note after the key change was also marked with a natural, as a reminder. The only place where this is still used is when the key signature changes to C major or A minor. If the naturals were not displayed, there would be nothing at all to show the key change.

What key has 4 Naturals?

There were 4 naturals: in the order F, C, G, D.

How do you write a natural sign?

A Natural Sign is an accidental that is used to cancel another accidental (a sharp, flat, double sharp or double flat). A Natural is written before the note (and after the letter name).