"Even" in Korean?
So I was looking through my Korean Grammar Workbook and there's a part that teaches about 조차 and 마저. They said 조차 and 마저 are both used for negative sentences, whereas 까지 is used for positive sentences, but then I went online to get more information about these three and the website I used said both 마저 and 까지 could be used for negative or positive situations. I was wondering which one was correct. Also, does -도 have the same meaning?

Question

Answer

There is a mistake in the upper repond. So I corrected it

I use the two for negative and positive situations.

그들조차 먹었어.
그들조차 먹지 않았어.

엄마마저 외출중이야.
엄마마저 외출하지 않았어.

-도 has the same meaning.
엄마도 외출중이야.
엄마도 외출하지 않았어.

Answer

I use the two for negative and positive situations.

엄마조차 모르는 사실이야.
엄마조차 알고 있는 사실이야.

엄마마저 외출중이야.
엄마마저 외출하지 않았어.

-도 has the same meaning.
엄마도 외출중이야.
엄마도 외출하지 않았어.