Use the Cornelsen Lernapp (free with book code) to do the interactive versions of the exercises. The app gives instant feedback.
Enter (published by Cornelsen). This is not your dusty, text-heavy grammar book from high school. It’s a colorful, exercise-driven, and communication-focused workbook that has become a secret weapon for learners across the globe. grammatik aktiv a1 b1
Unlocking German Grammar: A Deep Dive into “Grammatik aktiv A1–B1” Use the Cornelsen Lernapp (free with book code)