Learn Russian: Сколько грамм сыра?

The word сыра is the genitive singular form of сыр (cheese). We use the genitive case here because it expresses the idea of "of"—specifically, "of cheese". Whenever you measure a quantity of a substance, the substance follows in the genitive case.

Wait, is грамм singular or plural after сколько?

It is actually in the genitive plural form, because after сколько (how many), countable objects must be plural. For some masculine units of measurement like грамм (gram) and килограмм (kilogram), the everyday genitive plural form looks exactly like the basic dictionary form. You might see the formal version граммов in writing, but грамм is perfectly normal to say.

Can I just say Сколько сыра? instead?

Yes, you can! Сколько means both "how much" and "how many". If you ask Сколько сыра?, you are asking "How much cheese?" and directly combining the quantity word with the genitive singular. Adding грамм just makes your question more specific.

Why are there no verbs in this sentence?

In Russian, present-tense verbs like "is" or "are" are usually skipped. The sentence literally asks "How many grams of cheese?", and depending on the context, the listener will understand it means "How many grams of cheese are there?" or "How many grams of cheese do you want?".