By 3rd grade, kids need to know that words aren't just a string of letters—they are built like Lego blocks: The core meaning of the word.

People, places, or things (Кто? Что?).

What the subject is doing (usually a verb). Go to product viewer dialog for this item.

The changeable part at the end of the word used for connection. 2. Spelling Rules You Can't Forget These are the "golden rules" that prevent common mistakes:

Русский язык. 3 класс. Все основные правила

Tip: Try putting a question between the word and the particle. If it fits (e.g., "до (какой?) реки"), it’s a preposition.