In a lengthier and more linguistic explanation, I assume that very early on, masculine, feminine, and neuter had very different forms, like in Latin. However, over centuries of use, the sounds and spellings of Romanian changed in such a way that the neuter words most resembled masculine in their singular forms, but feminine in their plural forms. Which is how they are often described today.
The singulare of any neuter noun IS and behave like a masculine. The plural of any neuter noun is feminine and inflected as such.
Example: one juice = un suc (masculine)
the juice = sucul (masculine)
two juices = două sucuri (feminine) (not „doi” as it would be for masculine plural)
the juices = sucurile
No. Only one, two, twelve, and all numbers ending in them:
Two forms for one:
I have one pig. - Am un porc.
How many pigs do you have? One. - Câți porci ai? Unu.
I have one cow. - Am o vacă.
How many cows do you have? One. - Câte vaci ai? Una.
I have two pigs. - Am doi porci.
I have two cows. - Am două vaci.
I have twelve pigs. - Am doisprezece porci.
I have twelve cows. - Am douăsprezece vaci.
Numbers ending in one/two/twelve:
I have twenty one pigs. - Am douăzeci și unu
I have twenty one cows. - Am douăzeci și una de vaci.
I have twenty two pigs. - Am douăzeci și doi de porci.
I have twenty two cows. - Am douăzeci și două de vaci.
I have a hundred and twelve pigs. - Am o sută doisprezece porci.
I have a hundred and twelve cows. - Am o sută douăsprezece vaci.
* note that the două in "douăzeci" agrees in gender with the word "zeci" (tens).
** you can ignore the "de" particle for now :)