This comprehensive website contains tools that help students practice the theory aspects of music, ranging from simple staff identification all the way to the mechanics of chord progressions.  The website includes lessons to teach the techniques as well as quizzes that test student knowledge.  There are also tools that help students calculate certain musical relationships when they are composing their own music.

 

Website: http://www.musictheory.net
Subject: Music Theory
Grade Level: 3-12, or earlier depending on students’ skill levels
Price: Free