am is substituted for the Dative -4th Case ending e and for the endings of the Nominative 1st-Case and Accusative -2nd case in all numbers after the aṅga (stems) yuṣmad and asmad,
The ङे the ending of the Dative is exibited anomalously in the sutra without any case ending (compare 7.1.13, ङेः) प्रथमयोः means 'of the first and second cases'. Thus युष्मद् + ङे = तुभ्यद् + ङे 7.2.95 = तुभ्य + ङे (VII. I. 102) = तुभ्य + अम् (VII. I. 28) = तुभ्यम् (VI. I. I07) or 6.1.97; similarly मह्यम् ॥ So also युष्मद् + सु = त्वद् + सु 7.2.94 = त्व + सु 7.2.91 = त्व + सु 7.2.102 = त्व + अम 7.1.28 = त्वम् 6.1.97 or 6.1.107. Similarly अहम् ॥ So also युवाम् and आवाम् by 7.2.92 and 6.2.88; यूयम् and वयम् by 7.2.93 and 6.1.97 or 6.1.107, त्वाम् and माम् by 7.2.97 and 7.2.87; युवाम् and आवाम् as before.,