Reference for Eruvin 160:18

ואגב אורחיה קא משמע לן דשתי סעודות הויין שמונה עשרה גרוגרות:

R'Isaac son of Rab Judah replied: It was explained to me by my father that wherever the food for two meals, if divided between them,<span class="x" onmousemove="('comment',' The residents.');">⁵⁵</span> would not suffice to provide<span class="x" onmousemove="('comment',' Lit., 'reach'.');">⁵⁶</span> for each as much as the size of a dried fig,<span class="x" onmousemove="('comment',' Sc. if the number of the residents is eighteen or more. The food for two meals is equal in size to that of eighteen dried figs and when it is actually broken up into eighteen portions each is naturally slightly less than the size of a fig.');">⁵⁷</span> the residents are regarded as<span class="x" onmousemove="('comment',' Lit., 'they, (even) they'.');">⁵⁸</span>

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