þrjár

In a sentence

• Ég keypti þrjár bækur í gær.

  I bought three books yesterday.

  Here, 'þrjár' is used as the feminine nominative plural form to quantify the feminine noun 'bækur' (books).

• Við hittum þrjár vinkonur á kaffihúsinu.

  We met three female friends at the café.

  Here, 'þrjár' is used to quantify the feminine plural noun 'vinkonur' (female friends).

• Hún sér þrjár stjörnur á himninum.

  She sees three stars in the sky.

  Here, 'þrjár' reflects the counting of 'stjörnur' (stars), a feminine plural noun.