russian-grammar-school/docs/Grammar/Cases/Prepositional.md

Prepositional

Use it after:

• В
• На
• О

Nouns

Singular

Masculine	Feminine	Neutral
add -е	-а -> -е	-о -> -е
Some nouns (mostly single syllable) “-у” (but not after preposition “о”)		-я -> е
		-ь -> и

Plurals

Take the nominative singular form and:

• -а, -о, or ends with a consonant -> -ах
• otherwise replace last letter -> -ях

When to use "В"

Generally, use it when you're talking about something that is inside of something else.

When something is inside

• в доме
• в самолёте
• в квартире
• в столе

Continents, countries, cities, locations

• в Европе
• в Америке

When to use "На"

Generally, use it when you're talking about something that is on a horizontal surface or when you're talking about a process.

Surfaces

• на столе
• на пляже
• на этаже

Processes

• на уроке
• на работе
• на обеде

Directions

• на севере
• на юге
• на западе
• на востоке