Answer:The sentence "¿Cuántos años tienes?" is grammatically correct as written.
Explanation: Here's a step-by-step explanation of why it is correct:
1) The sentence starts with an inverted question mark (¿) to indicate that it is a question in Spanish.
2)The word "Cuántos" means "how many" in English, and it is used here to ask about the quantity of something.
3)The word "años" means "years" in English, which indicates that the question is asking about the number of years.
4)The verb "tienes" comes from the verb "tener," which means "to have" in English. In this sentence, it is conjugated in the second person singular form, matching the subject "tú" (you).
5) So, when we put all the words together, the sentence translates to "How many years do you have?" in English.
Overall, the sentence is grammatically correct because it follows the proper word order, verb conjugation, and question structure in Spanish. It is a common question used to ask someone about their age.