Reference for Bava Batra 206:4

<big><strong>מתני׳</strong></big> בית כור עפר אני מוכר לך מדה בחבל פיחת כל שהוא ינכה הותיר כל שהוא יחזיר ואם אמר הן חסר הן יתר אפילו פיחת רובע לסאה או הותיר רובע לסאה הגיעו יותר מכאן יעשה חשבון

— The matter is undecided. <b><i>MISHNAH</i></b>. [IF A MAN SAYS TO ANOTHER.] 'I SELL YOU A BETH <i>KOR</i> OF ARABLE LAND, MEASURED WITH THE ROPE',<span class="x" onmousemove="('comment',' I.e., exact measurements. ');">¹²</span> [AND] HE GAVE [HIM] LESS, [EVEN IF ONLY BY] A FRACTION, [AN EQUAL SUM] IS TO BE DEDUCTED [FROM THE PRICE]. [IF] HE GAVE MORE, [EVEN IF ONLY BY] A FRACTION, IT IS TO BE RETURNED [TO HIM]. IF, HOWEVER. HE SAID,<span class="x" onmousemove="('comment',' When the sale was being arranged. ');">¹³</span> 'MORE OR LESS,'<span class="x" onmousemove="('comment',' Instead of 'measured by the rope', thus implying the measurements of the beth kor are not exact. ');">¹⁴</span> THE SALE IS VALID EVEN IF HE GAVE [AT THE RATE OF] A QUARTER OF A <i>KAB</i> PER <i>SE'AH</i><span class="x" onmousemove="('comment',' Or seven and a half kab in the kor, i.e. 1/24 th A kor = thirty se'ah; a se'ah = six kab. ');">¹⁵</span>

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