Today we will have two separate but (in this case) related words. Supernumerary is the medical term for having an excess number of something. In the photo above a six year old has supernumerary digits. People can have supernumerary limbs, nipples, testicles, or organs. Supernumerary came into English around 1600 via Late Latin supernumerarius, meaning an excess number, originally describing troop numbers in a legion. Supernumerary also is currently used in non-medical contexts to indicate any surfeit above the expected amount.
Imparidigitate is the quality or condition of having different numbers of fingers or toes from one hand or foot to the other. Imparidigitate comes from the Latin negation prefix in-, im-, along with par, paris meaning equal and digitus meaning fingers.
Photo credit on photo.