I've never been great with theory, but I had a basic knowledge. Than I got lazy and have forgotten almost everything and my guitar teacher is getting on my ass about learning it again...as he should be. So basically, can someone tell me how many flats are in each key? So if my guitar teacher asks me how many flats are in the key of A I can be like

There are ___ flats in the key of A and they are ____

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The order of flats is BEADGCF, If you can remember the order, just count up to the note you have to get to, and that's it. So if you want the number of flats for A, it's B+E+A.

Same goes for the order of sharps, except it's backwards. FCGDEAB. Just remember with sharps that it's count up to the note you have to get to, and add 1. So C# would be F+C+G.
go clockwise around this:

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Circle of fourths and circle of fifths help.

But i'll give you a more direct answer:
Cb - 7 flats
C - all natural
C# - 7 sharps
Db - 5 flats
D - 2 sharps
Eb - 3 flats
E - 4 sharps
F - 1 flat
F# - 6 sharps
Gb - 6 flats
G - 1 sharp
Ab - 4 flats
A - 3 sharps
Bb - 2 flats
B - 5 sharps

Then there are the enharmonic names such as E# and Fb, A#, etc. But they can't be written out in a key signature. There are scales, sure. But double sharps and double flats aren't written out in key signatures.

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