Breakdown of Ona pracuje w pięciu organizacjach charytatywnych.
ona
she / it (f)
pracować
to work
w
in / on (a day)
pięć
five
Questions & Answers about Ona pracuje w pięciu organizacjach charytatywnych.
Why do we use pięciu instead of pięć here?
The preposition w meaning 'in' requires the Locative case. For numbers 5 and above, the Locative form is usually made by adding -u to the stem, so pięć becomes pięciu.
Wait, doesn't the number 5 force the following words into the Genitive case? Why isn't it pięciu organizacji?
That rule only applies when the number is in the Nominative or Accusative case. When a number 5 or above is in an oblique case like the Locative, Dative, or Instrumental, the Genitive rule disappears. Instead, the number, noun, and adjective all simply match in the same case. Here, they are all Locative plural.
What is the base form of organizacjach and why does it end in -ach?
The base form is the feminine noun organizacja (organization). The ending -ach is the standard Locative plural ending for almost all nouns in Polish, regardless of their gender.
Why does the adjective charytatywnych end in -ych?
Because it must match the noun in the Locative plural case. For adjectives, the Locative plural ending is -ych (or -ich after soft consonants). It looks exactly the same as the Genitive plural ending, but here it is strictly Locative to match w pięciu organizacjach.