Try the exercise first. Use the GDZ to check your "work in progress" so you actually learn the rules.
Prosveshchenie is one of the most common publishers in Russian schools. Their textbooks (like those by ) are standard, but the exercises can get tricky. GDZ helps you:
This is the most searched category. Look for Ladyzhenskaya (Ладыженская) and Baranov (Баранов) . Their 5th and 6th-grade textbooks are legendary for their dense exercises.