NumValue: numeric value
Low-value (<5) cardinal numbers in Slavic languages behave morphologically and syntactically differently from the rest, therefore some tagsets distinguish them (so far seen in Czech, Polish, and also Arabic, although it is not Slavic).
In Czech, number “one” agrees with the counted noun in gender, number and case. Number “two” agrees in gender and case and numbers “three” and “four” agree in case. These numerals behave similarly to adjectives. Numbers “five”, “six” etc. behave differently. If the case of the counted phrase is genitive, dative, locative or instrumental, the numeral agrees in case with the noun. However, if the case of the whole phrase is nominative, accusative or vocative, then the numeral dictates that the noun is in genitive. This behavior is similar to nouns modified by other nouns in genitive. (Note that this is why in the Czech PDT some numeral nodes are annotated as governing nouns instead of modifying them.)