The article focuses on the comparison of numbers in the Croatian and Czech languages. Although these are two typologically and genetically related languages, there are numerous differences in the category of numbers that cause problems not only for Czech speakers in mastering the Croatian language, but also for bilingual people (from Croatian-Czech mixed marriages or members of minorities) where we can find numerous interferences between these two languages.
In addition to the differences in the declination of numerals and their use (e.g. differences in the declination and use of basic numerals and compound numerical expressions and ordinal numerals), we pay special attention to similarities and differences in the expression of time - years, hours, the usual time of an event, etc. The comparison of language systems and the analysis of errors can serve as a reminder to speakers of places where errors often occur, but also to teachers and students of places that require special attention in the teaching of the mentioned languages.