This is part of the Distance Learning Version of S-Cubed Sight Singing Program for Beginners. This program is cumulative. You should purchase Lessons 1-5 Distance Learning Version and Distance Learning Bundle #2 with Lessons 6-10 and Distance Learning Version #3 with Lessons 11-15, Distance Learning Version Lesson 16, Distance Learning Version Lesson 17, and Distance Learning Version Lesson 18, and Distance Learning Version Lesson 19 before purchasing this. Purchasing bundles is more econo