In short

Use э́тот / э́та / э́то / э́ти (“this/these”, near) and тот / та / то / те (“that/those”, far) before a noun; they change to match its gender, number and case. To ask, use кто (who), что (what), како́й (which / what kind), чей (whose) and ско́лько (how many).

The rule

Demonstratives. A demonstrative points at something and tells you if it is near (э́тот) or far (тот). As a determiner it stands before a noun and must agree with it, exactly like a possessive (lesson 5):

• э́тот стол (m), э́та кни́га (f), э́то окно́ (n), э́ти столы́ (pl) = this / these.
• тот стол (m), та кни́га (f), то окно́ (n), те столы́ (pl) = that / those.

Do not confuse the agreeing determiner with the invariable pointer э́то from lesson 2. Standalone э́то means “this is / these are” and never changes - it works for any gender or number:

• Э́то стол. = This is a table. Э́то кни́га. = This is a book. Э́то столы́. = These are tables.
• Э́тот стол но́вый. = This table is new. (here э́тот agrees with стол)

So: pointer Э́то + naming something = invariable; determiner э́тот/э́та/э́ти + noun = agreeing.

Interrogatives. Question words go at the front, the rest of the sentence keeps normal order, and your voice rises (intonation - lesson 18):

• кто = who. It always takes masculine singular agreement, even about a woman or a group: Кто пришёл? (not пришла́/пришли́).
• что = what. It takes neuter singular agreement: Что случи́лось?
• како́й/кака́я/како́е/каки́е = which / what kind. Agrees with its noun like an adjective.
• чей/чья/чьё/чьи = whose. Agrees with the thing owned, not the owner.
• ско́лько = how many / how much. The counted noun goes into the genitive: ско́лько книг? (gen. pl.).

Кто and что also decline by case: кого́, кому́, чем… - the form depends on the verb or preposition. The other interrogatives decline too, but at A1 you mainly need their nominative forms.

Forms & patterns

Demonstratives - nominative (the form you use most at A1):

э́тот declined (for reference - тот changes the same way: того́, тому́, тем, той, тех):

* animate noun takes the genitive-like form (Я зна́ю э́того челове́ка).

Interrogatives that agree (nominative):

They decline too - како́й takes ordinary adjective endings (lesson 12): m/n како́го, како́му, каки́м, (о) како́м, f како́й, pl каки́х, каки́ми; чей drops its е and takes soft endings: m/n чьего́, чьему́, чьим, (о) чьём, f чьей, pl чьих, чьи́ми. At A1 you only have to recognise them: на како́м этаже́?

кто / что declined (these you should learn early):

Examples

Common mistakes

• э́тот кни́га -> э́та кни́га - the determiner must match gender; кни́га is feminine.
• Э́тот мой брат. (meaning “this is…”) -> Э́то мой брат. - to name/introduce, use the invariable pointer э́то, not э́тот.
• Кто пришла́? -> Кто пришёл? - кто always takes masculine agreement, even about a woman.
• Ско́лько кни́ги? -> Ско́лько книг? - ско́лько needs the genitive (here genitive plural).
• Чей су́мка? -> Чья су́мка? - чей agrees with the thing owned (су́мка is feminine -> чья).
• Что э́то челове́к? -> Кто э́то? - use кто for people, что for things.

Tips

• Memory hook: э́тот has the “here” vowel - э́тот = near; тот is short and points away = far.
• Treat э́тот/э́та/э́то/э́ти like an adjective: it copies the noun’s gender, number and case.
• Reflex pair: кто -> пришёл (masc.), что -> случи́лось (neut.) in the past tense.
• After ско́лько the noun is genitive: ско́лько вре́мени, ско́лько люде́й, ско́лько книг.
• A question = a statement + a question word in front + rising voice; the word order barely changes (lesson 18).