Learn Russian: Вместимость холодильника достигает литров восьмисот пятидесяти. - The capacity of the refrigerator reaches around eight hundred fifty liters.

The verb достигать (to reach) requires its object to be in the Genitive case. In Russian, when you decline a compound number, every single word and part changes case. For 800, восемьсот becomes восьмисот (both the "8" and the "100" decline). For 50, пятьдесят becomes пятидесяти.

Why is литров (liters) placed before the numbers?

Reversing the normal word order and placing the noun before the number is a standard way to express approximation in Russian. It translates to "about" or "around" 850 liters. If the capacity were exactly 850, it would be written in the standard order: достигает восьмисот пятидесяти литров.

Wait, does the number 50 (пятидесяти) force литров into the Genitive case here?

No, and this is a crucial rule for oblique (non-Nominative/Accusative) numbers! In the Nominative, numbers 5 and up force the following noun into the Genitive plural. But in oblique cases, the number and the noun simply agree in case. Here, the verb достигает forces the entire phrase into the Genitive case, so both the numbers and литров are independently in the Genitive.

The Genitive of 100 is ста, so why does 800 end in -сот (восьмисот) instead of -ста?