To change a major key signature to a minor key signature, add 3 flats or subtract 3 sharps. (Memorize G and D.) Remember the C sharp and C flat Major Key Signatures to remember where the accidentals are placed. Practice with Key Signature Identification set to minor keys from Ricci Adams' Musictheory.net.
http://www3.northern.edu/wieland/theory/keys/mi_sigs.htm
In the lesson about the major keys on the circle of 5ths you learned every key has a unique number of flats or sharps. The flats and sharps from key to key are not random . The flats and sharps of each key follow a specific, unchanging order that you need to memorize. This order is called the order of flats and the order of sharps.
https://www.studybass.com/lessons/harmony/the-order-of-sharps-and-flats/
Updated December 19, 2014. For quick reference use this table of key signatures in both major and minor keys. For further explanation, read this article on key signatures. Key Signatures.
https://www.thoughtco.com/table-of-key-signatures-2456460
Number 1. In determining a key signature for any named major key, it's important to know whether the key signature has sharps or flats. With the exception of the key of C major (no sharps or flats) and F major (one flat), any stand-alone letter is going to be a major key with sharps: G, D, A, E, B, F#, C#. Of course if a sharp follows the letter name (F#, C#), the key signature will have sharps.
http://spider.georgetowncollege.edu/music/burnette/MUS111/Keys.htm
E major (or the key of E) is a major scale based on E, with the pitches E, F♯, G♯, A, B, C♯, and D♯. Its key signature has four sharps. Its relative minor is C-sharp minor, and its parallel minor is E minor. Only two of Haydn's 104 symphonies are in E major, No. 12 and No. 29.
https://en.wikipedia.org/wiki/E_major
To figure out which major key you’re in, look at the last sharp in the key signature. If it’s on a line, go up to the next step; if it’s a space, go up to the next line. That’s what key you’re in. For example, if you have four sharps — F#, C#, G#, and D# — look to the last sharp — D#. If you go up to the next note, you find what key you’re in: E major. Flats: Flats are even easier to figure out. Like sharps, they always appear in the same order.
http://www.dummies.com/art-center/music/guitar/how-to-read-the-key-signature-to-determine-what-key-to-play/
At the top you have the key of C major, which has no sharps or flats in its key signature. Each stop on the Circle as you go down clockwise from C is a key with one more sharp than the previous key. Each stop as you go down counter-clockwise from C is a key with one more flat than the previous key.
http://www.dummies.com/art-center/music/guitar/how-to-read-the-key-signature-to-determine-what-key-to-play/
For key signatures with sharps, the key signature is the note name half step above the last sharp. This is the key of G because F# is the last sharp in the key signature. G is half step above F#. This is the key of E because E is half step above D#, which is the last sharp in the key signature. It is not the key of E# because there is no E# in this key signature. This is the key of C#.
http://www.musictheoryfundamentals.com/MusicTheory/keySignatures.php
Clue: Key with four sharps. Key with four sharps is a crossword puzzle clue that we have spotted 7 times. There are related clues (shown below). Referring crossword puzzle answers. EMAJOR.
http://crosswordtracker.com/clue/key-with-four-sharps-2/
The key of F has 1 flat. That means the flat must be the first flat (Bb). All the other letter names are natural notes. Now, starting on the root of the scale F, we can spell the key of F major — F, G, A, Bb, C, D, and E. As another example, the key of Ab major contains 4 flats.
https://www.studybass.com/lessons/harmony/the-order-of-sharps-and-flats/
what key has four sharps
The key of E or E major has four sharps. E major is the key that has 4 sharps.