Noun Cases

Table of endings of nouns of the 1^st declension (lesson about declensions).

I Declension
Case	Function	Preposi-tions	Singular	Plural
Nominative	Subject of the sentence (Who?)	–	а, я	ы, и
Accusative	Direct object	–	у, ю	ы, и, ей or zero ending
Genitive	Possession Negation Quantity	of, some, a little, a lot of, no	ы, и	ей or zero ending
Dative	Indirect object, Recipient	to	е	ам, ям
Prepositional	Object of speech or thoughts, Location	about, in, at	е	ах, ях
Instrumental	Means or Instrument	with, by	ой, ей	ами, ями

Let’s see how nouns девушка (girl) and книга (book) change in all cases:

I Declension
Case	Function	Preposi-tions	Singular	Plural
Nominative	Subject of the sentence	–	Девушка идет по мостовой. The girl is walking on the pavement. Книга лежит на столе. The book is on the table (litterally: The book is lying on the tabe)	Девушки идут по мостовой. The girls are walking on the pavement. Книги лежат на столе. The books are on the table.
Accusative	Direct object	–	Я знаю эту красивую девушку. I know this beautiful girl. Я вижу эту книгу. I see this book.	Я знаю этих красивых девушек. I know these beautiful girls Я вижу эти книги. I see these books.
Genitive	Posse-ssion Negation Quantity	of, some, a little, a lot of, no	Вещи девушки. Girl’s things. Книги там нет. There is no book.	Вещи девушек. Girls’ things. Книг там нет. There is no books.
Dative	Indirect object, Recipient	to	Подарить цветы девушке. Give flowers to a girl. Моей книге несколько столетий. My book is several centuries old.	Подарить цветы девушкам. Give flowers to girls. Моим книгам несколько столетий. My books are several centuries old.
Prepositional	Object of speech or thoughts, Location	about, in, at	Говорить о девушке. To talk about a girl. В этой книге много ошибок. There is a lot of mistakes in this book.	Говорить о девушках. To talk about girls. В этих книгах много ошибок. There is a lot of mistakes in these books.
Instrumental	Means or Instru-ment	with, by	Ссориться с девушкой. To quarrel with a girl. Убить паука книгой. To kill the spider with a book.	Ссориться с девушками. To quarrel with girls. Убить паука книгами. To kill the spider with books.

The 2^nd declension.

II Declension
Case	Function	Preposi-tions	Singular		Plural
			Masculine	Neutral
Nominative	Subject of the sentence (Who?)	–	–	о, е	а, я, ы, и
Accusative	Direct object	–	–	о, е	а, я, ы, и
Genitive	Posse-ssion Negation Quantity	of, some, a little, a lot of, no	а, я		ов, ев, ей or zero ending
Dative	Indirect object, Recipient	to	у, ю		ам, ям
Prepositional	Object of speech or thoughts, Location	about, in, at	е, и		ах, ях
Instrumental	Means or Instru-ment	with, by	ом, ем		ами, ями

For example, друг (friend) and лицо (face):

II Declension, masculine
Case	Function	Preposi-tions	Singular	Plural
Nominative	Subject of the sentence	–	Друг всегда поможет. A friend will always help.	Друзья всегда помогут. Friends will always help.
Accusative	Direct object	–	Увидеть друга. To see a friend.	Увидеть друзей. To see friends.
Genitive	Posse-ssion Negation Quantity	of, some, a little, a lot of, no	У него нет друга. He has no friend.	У него нет друзей. He has no friends.
Dative	Indirect object, Recipient	to	Позвонить другу. To call a friend. (In the meaning of calling by phone)	Позвонить друзьям. To call friends.
Prepositional	Object of speech or thoughts, Location	about, in, at	Гулять с другом. To walk with a friend.	Гулять с друзьями. To walk with friends.

The 3^rd declension.

II Declension, neutral
Case	Function	Preposi-tions	Singular	Plural
Nominative	Subject of the sentence	–	Лицо человека. A face of a human.	Лица людей. Faces of people.
Accusative	Direct object	–	Помнить лицо. To remember a face.	Помнить лица. To remember faces.
Genitive	Posse-ssion Negation Quantity	of, some, a little, a lot of, no	Выражение лица. Expression of a face. (Facial expression)	Выражение лиц. Expression of faces.
Dative	Indirect object, Recipient	to	По лицу текут слезы. Tears flow down the face.	По лицам текут слезы. Tears flow down the faces.
Prepositional	Object of speech or thoughts, Location	about, in, at	Вспомнить о лице. Call the face to memory.	Вспомнить о лицах. Call the faces to memory.
Instrumental	Means or Instru-ment	with, by	Людям с таким лицом суждено быть актерами. People with such a face are made to be actors.	Людям с такими лицами суждено быть актерами. People with such faces are made to be actors.

III Declension
Case	Function	Preposi-tions	Singular	Plural
Nominative	Subject of the sentence (Who?)	–	–	и
Accusative	Direct object	–	–	и, ей
Genitive	Possession Negation Quantity	of, some, a little, a lot of, no	и	ей
Dative	Indirect object, Recipient	to	и	ам, ям
Prepositional	Object of speech or thoughts, Location	about, in, at	и	ах, ях
Instrumental	Means or Instrument	with, by	ю	ами, ями

The examples of the nouns of the 3^rd declensions are мышь (mouse) and ночь (night):

III Declension
Case	Function	Preposi-tions	Singular	Plural
Nominative	Subject of the sentence (Who?)	–	Белая мышь. White mouse. Черная ночь. Black night.	Белые мыши. White mice. Черные ночи. Black nights.
Accusative	Direct object	–	Бояться мышь. To be afraid of a mouse. Любить ночь. To love the night.	Бояться мышей. To be afraid of mice. Любить ночи. To love the nights.
Genitive	Possession Negation Quantity	of, some, a little, a lot of, no	Усики мыши. Whiskers of a mouse. Создание ночи. Creature of the night.	Усики мышей. Whiskers of mice. Создания ночи. Creatures of the night.
Dative	Indirect object, Recipient	to	Дать сыр мыши. To give cheese to a mouse. Дать шанс этой ночи. To give a chance to this night.	Дать сыр мышам. To give cheese to mice. Дать шанс этим ночам. To give a chance to these nights.
Prepositional	Object of speech or thoughts, Location	about, in, at	Говорить о мыши. To talk about a mouse. Думать о ночи. To think about the night.	Говорить о мышах. To talk about mice. Думать о ночах. To think about the nights.
Instrumental	Means or Instrument	with, by	Жить с мышью. To live with a mouse. Гулять ночью. To walk at night.*	Жить с мышами. To live with mice. Гулять ночами. To walk at nights.

* Russian words meaning parts of the day (утром — in the morning, днем – in the afternoon, вечером – in the evening, ночью – at night) and seasons (летом – in summer, зимой – in winter, весной – in spring, осенью – in autumn) are oficially adverbs of time. However, their stems are nouns and they have exactly the same endings as nouns in instrumental case, that’s why I present them as such. I believe that it is better than to learn them by heart as adverbs without any logical explanation.