Aren't devce and holka the same meaning in different words? How do I know when to use which?
See https://forum.duolingo.com/comment/24403367/ and other discussions here.
In "neuter" lesson i typed "mlade devce", and got response "You have typos in your answer: mladá holka". ;)
You do indeed have typos there. The computer is free to show you any answer it wants.
Why is mlada holka given as an alternative answer in the neuter exercises Isn't mlada holka feminine ?
Why is devce neutral when it refers to a girl?
Because grammatical genders do not always correspond with "real-world" gender. Cf. German das Mädchen which is neuter as well.
Whats a different between Holka and Devce?
Is the 'l' in mladá silent?
What are the conditions to use mladá over mladé?
Check the Tips and notes of this skill, they explain how the gender affects the adjectives.
Not specific to this question but the accented letters list is in very pale grey on white. they are difficult to read and they sometimes do not show when pasted into the answer space