Notes De Musique is probably one of the best free and subscription-free apps available on Google Play to learn how to read music notes.

NotesDeMusique is an educational music game "Swiss knife" on music theory.
NotesDeMusique allows you to have fun while learning how to read music on a staff, develop your musical ear and also offers many additional features.

♪♫ Features
✓ 4 types :
. . .Reading music (notes)
. . .Ear training (notes)
. . .Reading music (chords)
. . .Ear training (chords)
✓ 4 modes :
. . .Training
. . .Timed game (finding the maximum score in a 1 or 2 minutes game)
. . .Survival mode (Game over if you make a mistake)
. . .Challenge mode (Challenge on 5, 10, 20, 50 et 100 notes !)
✓ 3 notation systems to display the notes name :
. . .Do Ré Mi Fa Sol La Si
. . .C D E F G A B
. . .C D E F G A H
✓ 4 clefs, on 4 octaves ! :
. . .Treble Clef
. . .Bass Clef
. . .Alto Clef
. . .Tenor Clef
✓ Sound & Vibrate mode
✓ Save scores by types and games modes
✓ Share your score on Twitter, Facebook, etc...

♪♫ Additional features
✓ Dictionary of chords
. . .Available chords are :
. . . . . .Major
. . . . . .Minor
. . . . . .7 (dom)
. . . . . .7 Major
. . . . . .7 Minor
. . . . . .Dim
. . . . . .Aug
✓ Help displaying the notes name

♪♫ Contact
If you find any bug or if you have any suggestions to help improve NotesDeMusique, please contact me !

♪♫ Website
NotesDeMusique website: https://www.notes-de-musique.com
NotesDeMusique changelog: https://www.progmatique.fr/freewares/freeware-9-NotesDeMusique.html

♪♫ NDM
NDM means NotesDeMusique, this is the name of the first educational music game that I developed. NotesDeMusique is a game designed to help you easily learn reading music notes on a staff.

You will find in the "software suite" NDM :
. . .NotesDeMusique, The first, which focuses on reading notes on a musical score (on a staff, for music theory)
. . .Specific applications for each musical instrument :
. . .Specific applications for each musical instrument :
. . . . . .NDM - Guitar, for guitar
. . . . . .NDM - Ukulele, for ukulele
. . . . . .NDM - Bass, for bass
. . . . . .NDM - Piano, for piano
. . . . . .NDM - Violin, for violin