katamiti no untin yori, ouhuku no hou ga sukosi yasui.

• 片道（かたみち） means one-way.
• 往復（おうふく） means round trip or there and back.

So in this sentence, it is comparing the fare for a one-way ticket with the fare for a round-trip ticket.

運賃（うんちん） means fare, especially for transportation such as trains, buses, or taxis.

It is more specific than a general word like 値段 (price).
So 片道の運賃 means the one-way fare.

Here, の links a noun to another noun.

• 片道の運賃 = one-way fare
• 往復のほう = literally the round-trip side

In the second part, の connects 往復 to ほう. This is natural because ほう acts like a noun in comparison expressions.

より marks the thing being used as the standard of comparison. It often means than.

So:

• 片道の運賃より = than the one-way fare

The full comparison pattern is:

• A より B のほうが + adjective

meaning:

• B is more adjective than A

In this sentence:

• 片道の運賃より、往復のほうが少し安い
• The round trip is a little cheaper than the one-way fare

In comparisons, ほう means something like side or option.

So 往復のほうが means:

• the round-trip option
• the round-trip one

This is part of a very common comparison pattern:

• A より B のほうが 安い
• B is cheaper than A

A native English speaker often wants to translate ほう directly, but it is usually better to think of the whole pattern instead of translating ほう by itself every time.

Yes. In Japanese, the item before より is the comparison standard, and the item before のほうが is the one being described.

So:

• 片道の運賃より = than the one-way fare
• 往復のほうが少し安い = the round-trip option is a little cheaper

That means:

• The round-trip fare is a little cheaper than the one-way fare.

This order can feel reversed to English learners at first, so it is worth memorizing the pattern:

• A より B のほうが… = B is more… than A

Yes, it does. Japanese often omits repeated words when they are obvious from context.

The full version would be:

• 片道の運賃より、往復の運賃のほうが少し安い。

But repeating 運賃 is unnecessary here, so it is omitted after 往復.

This kind of omission is extremely common in Japanese.

少し（すこし） means a little or slightly.

It modifies 安い:

• 少し安い = a little cheaper

So the speaker is not saying the round trip is much cheaper, only that it is somewhat cheaper.

安い is an い-adjective, and here it is the main predicate of the sentence.

• 安い = is cheap
• 少し安い = is a little cheap / is a little cheaper

You would use 安く when connecting to another word or verb, for example:

• 安くて便利です。 = It is cheap and convenient.
• 安くなりました。 = It became cheaper.

But in this sentence, 安い ends the statement, so the plain predicate form is correct.

In this comparison pattern, のほうが is the standard and very common form:

• A より B のほうが 安い

Here, が marks B as the thing being described.

You may also sometimes see は in other contexts for contrast, but のほうが is the usual pattern learners should remember first.

So this sentence sounds natural and standard as written.

Yes. A fully expanded version would be:

• 片道の運賃より、往復の運賃のほうが少し安い。

This makes the structure easier to see:

• 片道の運賃 = one-way fare
• 往復の運賃 = round-trip fare
• Aより Bのほうが 安い = B is cheaper than A

Japanese often drops repeated nouns when the meaning is clear.

Yes, if the context already makes it clear that you are talking about fares or tickets.

• 片道より、往復のほうが少し安い。

This would mean something like:

• Round trip is a little cheaper than one-way.

However, 片道の運賃より is more explicit and clearer, especially for learners or in writing.

No, the comma is not grammatically required.

You can write:

• 片道の運賃より往復のほうが少し安い。

The comma simply adds a small pause and can make the sentence a little easier to read.

Japanese punctuation is often more flexible than English punctuation.

The polite version is:

• 片道の運賃より、往復のほうが少し安いです。

Adding です makes the sentence polite.

So:

• 安い。 = plain style
• 安いです。 = polite style

Yes. This is one of the most useful Japanese comparison patterns:

• A より B のほうが + adjective

Examples:

• 電車よりバスのほうが安い。
  The bus is cheaper than the train.
• 犬より猫のほうが好きです。
  I like cats more than dogs.

So your sentence follows a very common and important structure. It is a great pattern to learn well.