Learn Russian: Мой внук — студент.

In Russian, the verb "to be" is almost always skipped in the present tense. Instead of using a word for "is", you simply place the subject and what it equals side by side. Literally, this reads as "My grandson student".

What is the purpose of the dash (—) between the words?

When a sentence links two nouns together in the present tense (like внук and студент) and the word "is" is dropped, Russian punctuation often uses a long dash in its place. It essentially acts like an equal sign.

Why use Мой here instead of Моя?

Possessive words like "my" must match the gender of the noun they describe. Since внук (grandson) is a masculine noun, we use the masculine form Мой. If the sentence was about a granddaughter (внучка), it would change to the feminine Моя.

How do we know it translates to "a student" if there is no word for "a"?

Russian does not have articles like "a", "an", or "the". The single word студент can mean "student", "a student", or "the student" depending on the context. You just add the "a" in your English translation to make it sound natural.