yeonpillo jalmos sseun geon jiugaero jiugo memojineun gabange neoheo.

잘못 쓴 means written incorrectly / wrongly written.

• 잘못 = wrongly, incorrectly
• 쓰다 = to write
• 쓴 = the adnominal (noun-modifying) form meaning written

So 잘못 쓴 건 literally means the thing that was written incorrectly.

Why 쓴 and not 쓰는?

• 쓰는 usually describes something in a more ongoing or general sense: something that is writing / something you write
• 쓴 refers to something that has already been written

Since the sentence is talking about something already written and needing to be erased, 쓴 is the natural form.

Yes. 건 is a shortened form of 것은.

• 것 = thing
• 은 = topic particle

So:

• 잘못 쓴 것은 → the thing that was written incorrectly
• 잘못 쓴 건 → same meaning, but more natural in everyday speech

This shortening happens a lot in Korean:

• 것은 → 건
• 것을 → 걸
• 것이 → 게

So 잘못 쓴 건 is a casual spoken-style way to say as for what was written incorrectly or the wrongly written part/item.

Here, -로 marks the tool or means used to do something.

So:

• 연필로 쓴 = written with a pencil
• 연필로 = with a pencil / in pencil

In this sentence, 연필로 잘못 쓴 건 means something like what you wrote incorrectly in pencil.

A useful way to think of -로 here is:

• 손으로 쓰다 = write by hand / with the hand
• 펜으로 쓰다 = write with a pen
• 연필로 쓰다 = write with a pencil

Yes, it is the same particle, but the specific meaning is slightly different because of the verb.

In both cases, -로 marks the means or instrument:

• 연필로 쓰다 = write with a pencil
• 지우개로 지우다 = erase with an eraser

So the basic grammar is the same: using X to do Y.

This is very common in Korean:

• 가위로 자르다 = cut with scissors
• 칼로 썰다 = slice with a knife
• 지우개로 지우다 = erase with an eraser

It does sound repetitive in English, but in Korean this is totally normal.

• 지우개 = eraser
• 지우다 = to erase

These words are related in meaning, so putting them together is very natural in Korean, just like:

• 칼로 자르다 = cut with a knife
• 빗으로 빗다 = comb with a comb

English often prefers to avoid repetition, but Korean does not mind it here. So 지우개로 지우다 is just a straightforward, natural expression meaning erase it with an eraser.

지우고 is the -고 form of 지우다.

The ending -고 links actions, often meaning:

• and
• and then
• after doing

So in this sentence:

• 지우고 메모지는 가방에 넣어
• erase it, and put the memo paper in the bag

It connects the first instruction to the second one.

Here the flow is basically:

1. erase the wrongly written part
2. put the memo paper in the bag

In casual instructions, -고 is very common for chaining actions.

-는 is the topic particle. Here it marks 메모지 as the topic of the second instruction.

• 메모지는 가방에 넣어
• literally: As for the memo paper, put it in the bag

The topic particle often gives a slight sense of contrast or shift of focus. In this sentence, it helps separate the two things being talked about:

• the wrongly written part → erase it
• the memo paper → put it in the bag

So 메모지는 can feel like:

• as for the memo paper...
• the memo paper, though,...
• now, the memo paper...

This kind of topic marking is very common when giving instructions about different items.

The object is understood from context: 메모지.

Korean often omits words that are obvious from the situation.

So:

• 메모지는 가방에 넣어
• literally looks like: As for the memo paper, put in the bag
• but naturally means: Put the memo paper in the bag

The object does not need to be repeated because 메모지는 already introduced it as the topic.

If you wanted to state the object more explicitly, you could say something like:

• 메모지는 가방에 넣어
• 메모지를 가방에 넣어

These are slightly different in nuance:

• 메모지는 = topic/emphasis/contrast
• 메모지를 = direct object marker, more straightforward

Both can mean put the memo paper in the bag, but the nuance is different.

메모지는 가방에 넣어

• -는 marks 메모지 as the topic
• can suggest a contrast or item-by-item instruction
• feels natural in a sequence like:
  • this, do that
  • that, do this

메모지를 가방에 넣어

• -를 marks 메모지 simply as the direct object
• feels more neutral and direct

In your sentence, 메모지는 fits well because the speaker is giving separate instructions about different things.

넣어 is a casual, plain-style command/request.

Compare:

• 넣어 = put it in / put it in there
  
  • casual
• 넣어요 = put it in
  
  • polite, softer, conversational
• 넣으세요 = please put it in
  
  • polite, often more clearly directive

So the original sentence sounds like casual instructions, perhaps to a child, friend, or someone the speaker is speaking informally to.

The same idea applies to the first action too: the sentence is understood as a casual instruction sequence.

It is basically two commands joined into one sentence.

The two parts are:

• 연필로 잘못 쓴 건 지우개로 지우고
• 메모지는 가방에 넣어

So the speaker is giving a sequence of instructions:

1. erase what was written incorrectly in pencil
2. put the memo paper in the bag

Korean often links commands this way with -고 instead of making two completely separate sentences.

The subject is omitted because it is obvious from context.

In English, commands usually also omit you:

• Erase it and put the memo paper in the bag.

Korean works the same way. In instruction sentences, the person being spoken to is usually understood, so there is no need to say it.

If Korean explicitly included the subject, it would often sound unnecessary unless there were a special reason to emphasize it.

Most naturally, it refers to the part/item that was written incorrectly in pencil.

The structure is:

• 연필로 = with a pencil
• 잘못 쓴 = written incorrectly
• 건 = thing / the one

So the phrase groups together as:

• the thing written incorrectly with a pencil

In real usage, the exact scope can depend on context, but the intended meaning is usually clear: something written in pencil has a mistake, and that mistaken writing should be erased.

메모지 means memo paper, note paper, or sometimes a small piece of paper used for notes.

Depending on context, it could refer to:

• a note sheet
• a memo slip
• a small paper for writing reminders

It does not always mean a sticky note specifically, though in some contexts it could overlap with that idea. The basic sense is simply a piece of paper used for notes/memos.