The affix kan is added to an ordinal number in the sense of 'acquiring a subject after so many attempts' and there is optionally the elision of the affix denoting the ordinal number.,
The word तावतिथं 5.2.53 stands here as a type of all words ending in affixes denoting i.e. ordinals. The word ग्रहण means 'acquired or Iearned hereby'. This qualifies the base. Thus द्वितीयेन रूपेण ग्रन्थं गृह्णाति = द्विकं ग्रहणम् or द्वितीयकं ग्रहणम् 'the acquisition of the knowledge or book by the second time' i.e, \successful mastery by the second time\. So also त्रिकं or त्रितीयकम्, चतुष्कम् or चतुर्थकम् ॥
Vart:- When the word, formed by the affix kan, means the person who acquires after so many times then the elision of the पूरण affix is compulsory and not optional. Thus षष्ठेन रूपेण ग्रन्थं गृह्णाति = षट्को देवदत्तः 'Devadatta who learns the book for the sixth time' i.e. 'who succeeds in learning the book at the sixth attempt'. Similarly पंचकः, चतुष्कः ॥ The word ग्रहण here is confined to books only and to nothing else.,