Questions & Answers about У меня есть девяносто три рубля.
Why is rubles written as рубля (genitive singular) when 93 is a plural amount?
In Russian, the last word of a compound number decides the case of the noun. Because 93 ends in три (three), you follow the rule for the number 3: it takes the genitive singular (рубля). If the amount was 95 (девяносто пять), you would use the genitive plural (рублей).
Does девяносто follow a pattern, or is it an exception? I expected it to end in -десят like 50 or 60.
It is an exception! While 50 through 80 end in -десят (which literally means "tens"), 40 (сорок) and 90 (девяносто) have their own unique forms. You just have to memorize them as special cases.
Do I need to change три to match the gender of рубль?
No, the number три (3) is the same for masculine, feminine, and neuter nouns. Only the numbers 1 (один / одна / одно) and 2 (два / две) change to match the noun's gender. For example, if you had 92 rubles, you would use the masculine form of two: девяносто два рубля.
Could I leave out есть and just say У меня девяносто три рубля?
Yes, absolutely! Including есть emphasizes the fact of possession (like saying "I do have 93 rubles"). If you just want to casually state the amount of money you have on you, dropping есть is very natural and common in everyday speech.