Learning Music Theory involves the “why” and “how” of music. When learning to play the piano, music theory is a great companion. I make it a point to include music theory in each piano lesson.
I recommend Heather Savage, who has taught my four children advanced music theory, for more in-depth theory.
Feel free to explore and practice skills on the computer with these online games:
Various Theory Lessons & Games
Music Glossary, (Thanks Anna for suggesting!)
Theory Lessons and Exercises from beginning to advanced
Also useful for the budding composer in each young student is music writing software. Musescore is a free download with many great options.
Online notation software (in case downloading is a problem):
Noteflight (Bonus: exports and imports to/from Soundtrap)
If you have any questions regarding these games or the software, don’t hesitate to contact me!