इजादेः सनुमः

A कृत् affix ordained after a verb beginning with an इच् vowel, having the augment नुम् in it, and ending with a consonant, changes it s न् into ण् , when preceded by an उपसर्ग having in it the cause of change.
The word हलः of the last sutra is understood here. But contrary to the construction put upon it in the last sutra, here it means हलन्तात्, by the natural rule of construction as given in 1.1.72. We must interpret it so here, because it is impossible for an इजादि root to commence with a हल्; while to have done so in the last aphorism would have been redundant.

Thus प्रेङ्खणम्, परेङ्खणम् from इखि गत्यर्थः; the नुम् is added because it is इदित् ॥ प्रेङ्गणम्, परेङ्गणम्, प्रोम्भणम् परोम्भणम् ॥ In उम्भ पूरणे the nasal is part of the root. The rule will not apply to प्रेन्वनम्, because नुम् here means the anusvara generally 8.4.2 though the change would have been valid by the general rule, 8.4.29 this sutra makes a नियम or restriction. That is, only in the case of इजादि सनुम् verbs the change takes place, not in other सनुम् verbs. Thus प्रमङ्गनम्, परिमङ्गनम् from the root मगि सर्पणे ॥

This rule does not affect rule 8.4.30, relating to ण्यन्त verbs, for those verbs cannot be said to end with a consonant. Moreover, we have used the word विहितः in explaining the sutra, in order to indicate this fact, that the krit-affix must be ordained after a consonant-ending verb. In the case of causative verbs, the krit-affix is ordained after a vowel-ending (णि) verb, and the vowel is elided after the adding of the affix. So that before the adding of the affix, the verb did not end in a consonant.