У книзі сто сторінок.

Both у and в can mean in. Ukrainian often switches between them for ease of pronunciation and flow.

Here, у книзі sounds natural, but в книзі is also correct. This is a very common alternation in Ukrainian:

• у місті
• в автобусі
• у школі
• в Україні

So the choice is often about sound, not meaning.

Because after у / в when you mean location, Ukrainian usually uses the locative case.

So:

• dictionary form: книга = book
• locative singular: у книзі = in the book

This is why the ending changes from -а to -і.

Книзі is in the locative singular.

The locative is commonly used after prepositions such as:

• у / в = in
• на = on / at
• при = by / in the presence of

So у книзі literally means in the book, with книзі showing location.

In the present tense, Ukrainian very often leaves out the verb to be.

So У книзі сто сторінок literally looks like:

• In the book — one hundred pages

But the natural English meaning is:

• There are one hundred pages in the book or
• The book has one hundred pages

This kind of verb omission is completely normal in Ukrainian.

Because after сто (one hundred), the noun goes in the genitive plural.

So:

• сторінка = page
• сторінок = of pages

This is part of a broader number pattern in Ukrainian:

• 1 сторінка
• 2, 3, 4 сторінки
• 5 сторінок
• 100 сторінок

So сто сторінок is the correct form.

No. It is part of the general pattern with many numerals.

A useful simplified rule:

• after 1 → nominative singular
  одна сторінка
• after 2, 3, 4 → a special plural form that usually looks like genitive singular
  дві сторінки, три сторінки
• after 5 and higher → genitive plural
  п’ять сторінок, десять сторінок, сто сторінок

So сто follows the same 5+ pattern.

Yes. Книга має сто сторінок is also correct and means The book has one hundred pages.

The difference is mostly in structure and emphasis:

• У книзі сто сторінок = There are one hundred pages in the book
• Книга має сто сторінок = The book has one hundred pages

Both are natural. The version with у книзі is a very common way to express what something contains.

Ukrainian word order is more flexible than English word order.

Starting with У книзі puts the setting first:

• In the book, there are one hundred pages

This is very natural. It introduces the place or context before saying what is there.

You could also hear:

• Сто сторінок у книзі

But У книзі сто сторінок is the most neutral and standard order here.

It can naturally correspond to both in English.

Literally, it is closer to:

• There are 100 pages in the book

But in normal English, we often translate it as:

• The book has 100 pages

So the Ukrainian sentence focuses on what is contained in the book, while English may prefer the has structure.

A rough pronunciation guide:

• книзі ≈ knyi-ZEE
• сторінок ≈ sto-ree-NOK

The stress is important:

• книзі
• сторінок

And the whole sentence is roughly:

• u kny-ZEE sto sto-ree-NOK

This is only an approximation, but it helps with the rhythm.

Usually it means in the book, and that can be either:

• physically inside it, such as pages, pictures, notes
• in its content, such as information or ideas

In this sentence, because we are talking about pages, the meaning is physical and straightforward: the book contains that many pages.

The dictionary form is сторінка = page.

Its forms here are:

• сторінка — singular
• сторінки — used after 2, 3, 4
• сторінок — genitive plural, used after 5+, including 100

So in this sentence, сторінок is not a separate word to memorize by itself; it is a grammatical form of сторінка.