Questions & Answers about У официанта есть семь заказов и десять монет.
Why do the words for orders and coins take special endings in this sentence?
Because of the numbers! In Russian, numbers 5 and up (like семь and десять) require the noun that follows to be in the Genitive plural case.
How is the Genitive plural formed for заказов?
The dictionary word is заказ (order), which is a masculine noun ending in a hard consonant. For these types of masculine nouns, you add -ов to make the Genitive plural.
Why doesn't монет have a special ending like -ов?
The dictionary form is монета (coin), which is a feminine noun ending in -а. To form the Genitive plural of these feminine nouns, you simply drop the -а to create a zero ending (no ending at all). So, монета becomes монет.
Why does the sentence start with У официанта?
This is the classic Russian possession structure. Instead of using a direct verb for possession, Russian says At the waiter there is using У + Genitive case + есть. Официанта is the Genitive singular form of официант.