संख्याया विधार्थे धा

Operational rule vidhi

The affix धा comes after a प्रातिपदिक (Nominal Stem) denoting a Numeral when it means the mode or manner of an action.

Word by word (padaccheda)

Left context संख्यायाः pañcamī · ekavacanaRight context विधार्थे saptamī · ekavacanaSubstitute / term धा prathamā · ekavacana

Left context Pañcamī (5th case): "after X", the operation applies to what follows (1.1.67 तस्मादित्युत्तरस्य). Also used for limits and sources.
Right context Saptamī (7th case): "when X follows", the operation applies to what precedes (1.1.66 तस्मिन्निति निर्दिष्टे पूर्वस्य). Also a condition or domain ("in the sense of").
Substitute / term Prathamā (1st case): in operational rules, the substitute or the thing introduced; in definitions, the term or its referent.

Dotted words are technical terms. Hover or tap one to see its card.

Full reading

संख्यायाः विधार्थे धा

Pāṇini leaves out words that carry over from earlier sūtras. Expand to see the rule as a reader actually understands it.

Commentary

The affix धा comes after a प्रातिपदिक (Nominal Stem) denoting a Numeral when it means the mode or manner of an action.
The word विधा and प्रकार have the same meaning. The adverbs so formed apply to every kind of action. Thus एकधा भुङ्क्ते 'he eats once'. द्विधा गच्छति 'he goes twice'. Similarly त्रिधा, चतुर्धा, पञ्चधा ॥

Śrīśa Chandra Vasu, The Ashtadhyayi of Panini (1897), via ashtadhyayi.com.