U vrtić nosi malu slagalicu i novu bojanku.

Because u can take different cases depending on meaning:

• u + accusative = movement into / to
• u + locative = location in / at

So:

• U vrtić nosi... = He/She is taking ... to kindergarten
• U vrtiću nosi... would sound like In kindergarten he/she carries...

Here the idea is destination, so vrtić is in the accusative singular.

Nosi is the 3rd person singular present form of nositi.

It can mean:

• carries
• is carrying
• takes
• is taking / bringing

The exact English translation depends on context. Croatian present tense is often broader than English, so nosi can describe:

• something happening now
• something habitual
• something generally true

In this sentence, it most naturally means something like He/She is taking or He/She carries/brings.

Because they are direct objects of the verb nosi, so they must be in the accusative case.

Both nouns are:

• feminine
• singular

So both the nouns and their adjectives change form:

• mala slagalica → malu slagalicu
• nova bojanka → novu bojanku

The adjective must agree with the noun in:

• gender
• number
• case

So:

• malu matches slagalicu
• novu matches bojanku

Yes, the subject is not stated explicitly, and that is very normal in Croatian.

The form nosi already tells you it is:

• he/she/it carries
• or sometimes one carries, depending on context

Croatian often leaves out subject pronouns when the verb ending already shows the person and number.

So the sentence could mean:

• He is taking a small puzzle and a new coloring book to kindergarten
• She is taking a small puzzle and a new coloring book to kindergarten

You need context to know whether it is he or she.

Croatian does not have articles like English a/an and the.

So a noun like slagalicu can mean:

• a puzzle
• the puzzle

And bojanku can mean:

• a coloring book
• the coloring book

Context tells you which is meant. The adjectives malu and novu help specify the nouns, but they do not function like articles.

Yes. Croatian word order is more flexible than English because case endings show grammatical roles.

The original sentence:

• U vrtić nosi malu slagalicu i novu bojanku.

could also be rearranged, for example:

• Nosi malu slagalicu i novu bojanku u vrtić.
• Malu slagalicu i novu bojanku nosi u vrtić.

These all keep basically the same core meaning, but the emphasis changes:

• starting with U vrtić emphasizes the destination
• starting with Nosi sounds more neutral
• starting with Malu slagalicu i novu bojanku emphasizes what is being taken

• slagalica usually means puzzle
• bojanka means coloring book

A small nuance:

• slagalica often refers to a jigsaw-style puzzle or something made by putting pieces together
• bojanka is specifically a book for coloring, usually for children

So the sentence sounds very natural in a preschool/kindergarten context.

It can mean either, depending on context.

Croatian present tense often covers both:

• right now: He/She is taking...
• habitually / regularly: He/She takes...

For example:

• If you are describing what someone is doing at this moment, nosi = is taking / carrying
• If you are describing a routine, nosi = takes

Without more context, both are grammatically possible.

Because i simply links the two objects:

• malu slagalicu
• novu bojanku

So the structure is:

• [object 1] i [object 2]

Croatian does not need to repeat the conjunction here. Each noun keeps its own adjective, and i joins the two full noun phrases:

• malu slagalicu
• novu bojanku

This works just like English a small puzzle and a new coloring book.

Because these are feminine singular accusative adjective forms.

Compare:

• nominative: mala slagalica, nova bojanka
• accusative: malu slagalicu, novu bojanku

For many feminine adjectives, the ending changes like this:

• -a → -u

So:

• mala → malu
• nova → novu

This is one of the most common adjective patterns learners meet in Croatian.