دستورِ زبانِ پارسی

Proportional numerals are nominal numerals involving arithmetic ratios. They are generated in the following ways:

1. To compare the absolute values of two counting numerals, the second numeral can attribute the first. In this case, the attribute appears as a locative adverbial (in the form of an adpositional phrase with the preposition /bæ/, /bær/ or /æbær/):

   نتیجه‌یِ چهار به یک /ʧæhɒr bæ jek/

   نتیجه‌یِ چهار بر سه /ʧæhɒr bær se/

2. To compare two parts of a whole value, the proportional numeral is generated by copulative composition with the interfix /-ɒ-/:

   نصفانصف /nesf/ + /-ɒ-/ + /nesf/ → /nesf-ɒ-nesf/

   نه راستیّ و درستی هر آن مَثَل که زدند

   اگر نه جملـه دروغ‌ست، هست نیمانیم /nim-ɒ-nim/

   Suzani Samarqandi (12^th Century AD)