"This is a potato."

Translation: Αυτή είναι μία πατάτα.

[JacobPast177]

How about an optional Αυτό είναι μια πατάτα.? (I.e. in the sense of Αυτό [το πράγμα εδώ] είναι μια πατάτα.) Currently it is not accepted.

[mizinamo]

I've added it now.

[newlightmx]

The "μια" always throws me off since its pronounced as in "mine" in spanish