The most important thing in life are making money, traveling aboard , and to live well.

are begin used correctly

I feel like the word should be replaced with the word is?

This sentence needs a parallel structure. Since two phrases in the last are gerund phrases -- making money, traveling abroad -- the last one must also be a gerund phrase.

Change "to live well" to "living well."

long before his death, Pablo Picasso became the most important artists in history. which word is not used correctly.

Yes, you are correct. The word "are" should be replaced with the word "is" in this sentence. So it should be: "The most important thing in life is making money, traveling abroad, and living well."

You are correct that the word "are" should be replaced with the word "is" in this sentence. The subject of the sentence is "the most important thing in life," which is singular. Therefore, the verb should also be singular, which is "is."

To verify this, you can break down the sentence and analyze its components:
- Subject: "the most important thing in life" (singular)
- Verb: "are" (plural)
- Object: "making money, traveling abroad, and to live well" (plural)

Since the subject is singular, the verb should also be singular. So the corrected sentence would be: "The most important thing in life is making money, traveling abroad, and living well."