I had- Двадцять один міста, і двадцять один села .. thought that the plural form of misto was mista. also thought plural form of selo was sela? can someone help me figure out how conjugation of these nouns ending in O are changed?
Село and місто are neuter, so you should have written одне instead of один. Plural of місто is indeed міста and of село - села. But with numbers ending in one you should use accusative singular which is місто and село (check Tips & Notes)