deriv SD cv (1092) ashtadhyayi.com hei.de L 1092 ETT STT a 4.1.115 ALPH OLDHOMEPAGE NEWHOMEPAGE

mAtur ut saGkhyA-sam-bhadra-pUrvAyAH

मातुरुत्संख्याॱसम्भद्रॱपूर्वायाः ONPANINI 41115

After sam सम्, bhadra भद्र or a numeral, to express a descendant, replace mAtR- मातृॱ with ur उर् and add /aN''.

dvimAturaH द्विमातुरः "having two moms".

sUtra says ut उत्, why did you translate urS उर्ष्

That's left as an exercise!