It sounds like you're looking for help with the for the 3rd-grade Russian textbook by L. Ya. Zheltovskaya and O. B. Kalinina .
Working with unstressed vowels, silent consonants, and the use of the hard sign (ъ) and soft sign (ь). gdz po russkomu za 3 klass l.ia.zheltovskaia
If you are stuck on a specific rule, here is a quick refresher on what this textbook usually covers at this stage: It sounds like you're looking for help with
Since this curriculum is part of the "Planet of Knowledge" (Planeta Znaniy) series, the exercises often focus on word structure, parts of speech, and spelling rules. Where to find the full solutions parts of speech
Finding the root ( koren ), prefix ( pristavka ), suffix ( suffiks ), and ending ( okonchanie ).