The paper focuses on the semantics of quantitative NPs. In Russian, NPs with collective numerals and pluralia tantum nouns, and NPs with plural cardinals and plural nouns in Estonian seem to possess comparable structure and functions. The research aims at a better understanding of whether Russian collective numerals and Estonian plural cardinals simply indicate the number of items referred to by the noun. The analysis suggests that cardinals within quantitative NPs closely correlate with the type of the noun and their plural form indicates the abilities of the "counted" object to be part of a set or/and represent its set. The results show that while some functions of plural cardinals and collective numerals in quantitative NPs are quite similar, others differ significantly.