You encounter an alien and overhear her counting 0 1 2 3 4 1

You encounter an alien and overhear her counting: 0 1 2 3 4 10 11 12 13 14 20… How many
digits (fingers, thumbs) do you think this species possesses (on all hands, paws, fins)?

Solution

the alien have two hands with each having 5 fingers and

hve two wings just like Bat which cant fold its fingers inorder to count(each wing have 5 fingers which unfoldable).

so totally 20 fingers with 10 fingers foldable and 10 unfoldable

and two wings