kono hottikisu ha tiisai desu ga, kopiiyousi wo zyuumai matomeraremasu.

は marks the topic of the sentence.

So このホッチキスは means something like:

• As for this stapler, ...
• This stapler, ...

The speaker is introducing this stapler as the thing they are going to comment on.

If you used が instead, it would sound more like you are specifically identifying this stapler as the one with that property, rather than simply talking about it as the topic.

小さい is an い-adjective, so it does not take だ.

• Correct: 小さいです
• Incorrect: 小さいだ

With い-adjectives, the adjective itself already functions as the predicate, and です is added only to make it polite.

So:

• 小さい = is small
• 小さいです = is small (polite)

This is different from な-adjectives and nouns, which do use だ / です:

• 静かだ / 静かです
• 先生だ / 先生です

Yes, here が connects two clauses and means something like:

• but
• although
• even though

So the sentence structure is:

• このホッチキスは小さいですが、...
• This stapler is small, but ...

The idea is that being small might make you expect weaker performance, but the second clause gives a surprising result: it can handle ten sheets.

In polite Japanese, が is a very common way to connect clauses. In casual speech, you might also hear けど or けれど.

Here, まとめられます is the potential form, meaning can do something.

It comes from the verb まとめる, which means:

• to gather together
• to put together
• to bundle together
• in this context, to staple together

So:

• まとめる = to staple/group together
• まとめられます = can staple/group together

It can look like a passive form, because for many る-verbs, the passive and potential forms look the same:

• 食べる → 食べられる
• まとめる → まとめられる

So context decides the meaning.

Here, コピー用紙を十枚まとめられます clearly means:

• can staple ten sheets of copy paper together

not

• ten sheets of copy paper are stapled together

Because コピー用紙 is the thing being acted on by the verb まとめる.

So:

• コピー用紙を = copy paper / the sheets of copy paper as the object
• まとめられます = can staple together

Even though the sentence includes a number, the paper is still the direct object of the action.

A useful way to understand it is:

• コピー用紙を十枚 = ten sheets of copy paper
• まとめられます = can staple together

Japanese often places the counter phrase near the noun or object like this.

十枚 means ten sheets.

• 十 = ten
• 枚 = counter for flat, thin objects

枚 is the correct counter for things like:

• sheets of paper
• plates
• shirts
• tickets

Since コピー用紙 is sheet-like, 枚 is used.

So:

• コピー用紙を十枚 = ten sheets of copy paper

A learner might expect something like 十のコピー用紙, but Japanese normally uses counters instead.

It actually could be.

Both of these are possible:

• コピー用紙を十枚まとめられます
• 十枚のコピー用紙をまとめられます

The difference is mostly in phrasing and focus.

In this sentence:

コピー用紙を十枚 sounds natural and straightforward when talking about how many sheets the stapler can handle.

With 十枚のコピー用紙:

the number phrase more directly modifies the noun, like:

• ten sheets of copy paper

So both are grammatical, but the version in your sentence is very common in ordinary Japanese.

Yes, the basic meaning of まとめる is something like:

• to gather together
• to put together
• to organize
• to bundle

But in context, Japanese often uses it for fastening sheets together with a stapler.

So with ホッチキス, まとめる naturally means:

• to staple together

This is a good example of how Japanese often uses a broader verb, and the exact English translation depends on context.

Yes, ホッチキス is a very common Japanese word for stapler.

It comes from the name Hotchkiss, originally a brand name. This kind of brand-name borrowing is not unusual in Japanese.

So even though the origin is unusual, for learners you can safely treat ホッチキス as the normal everyday word for stapler.

Depending on context, Japanese speakers may also use ホッチキス for the stapler itself or even informally for the action of stapling.

No, this spacing is mainly for learners.

Normal Japanese would usually be written like this:

このホッチキスは小さいですが、コピー用紙を十枚まとめられます。

Japanese normally does not use spaces between words the way English does. Textbooks and beginner materials often insert spaces to make word boundaries easier to see.

So the spaced version is helpful for study, but not standard adult writing.

Yes. In normal writing, it would usually appear as:

小さいですが

That is just:

• 小さいです
  • が

The sentence you were given separates parts with spaces for learning purposes, but in ordinary Japanese it is written as one continuous phrase.

So:

• learner-style spacing: 小さい　です　が
• normal writing: 小さいですが

Both represent the same grammar.

Yes, Japanese often leaves out subjects when they are obvious from context.

Here, the understood subject is this stapler:

• このホッチキスは ... まとめられます
• As for this stapler, it can staple together ten sheets of copy paper

Japanese does this all the time. Once the topic has been stated, later parts of the sentence often omit anything that is already understood.

So even though English wants it can staple..., Japanese does not need to repeat it.