If you are using this book to "spishu" (cheat/copy) or just to study better, keep these topics in focus as they are the 6th-grade heavyweights:
The tricky spelling rules that appear in every dictation. 6 klass russkii iazyk buneev spishu
Deep dives into Nouns, Adjectives, and Numerals. If you are using this book to "spishu"