Reference for Arakhin 15:14

טועה שאמרה גיום אחד טמא ראיתי פתחה שבעה עשר שני ימים טמא ראיתי פתחה שבעה עשר דשלשה ימים טמא ראיתי פתחה שבעה עשר ארבעה ימים טמא ראיתי פתחה ששה עשר חמשה ימים טמא ראיתי פתחה חמשה עשר ששה ימים טמא ראיתי פתחה ארבעה עשר שבעה ימים טמא ראיתי פתחה שלשה עשר שמונה ימים טמא ראיתי פתחה שנים עשר התשעה ימים טמא ראיתי פתחה אחד עשר עשרה ימים טמא ראיתי פתחה עשרה אחד עשר פתחה תשעה

[If she says,] 'I saw uncleanness for six days', her re-count commences after fourteen days; [if she says,] 'I saw uncleanness for seven days', her re-count commences after thirteen days; [if she says,] 'I saw uncleanness for eight days', her re-count commences after twelve days; [if she says,] 'I saw uncleanness for nine days', her re-count commences after eleven days; [if she says,] 'I saw uncleanness for ten days', her re-count commences after ten days;<span class="x" onmousemove="('comment',' The same consideration, that the first two days may be the last days of her zibah period, necessitates, in the case of the five-day flow, the counting of at least fifteen days, the remaining four of the niddah plus the complete eleven of the zibah periods, in the case of the six-days flow, the counting of the remaining four days of the niddah plus the eleven of the zibah period; of three remaining niddah plus eleven zibah days in the case of a seven-day flow; of two niddah and eleven zibbah days in the case of an eight-day flow, and of one remaining day of niddah and eleven days of zibah in the case of a nine-day flow. So that the number of the days necessary moves from seventeen to twelve, on the above considerations. In the case of a ten-day flow, then, even on the assumption that the first two days had belonged to the zibah period, the zibah period recommenced after the seven days of niddah, i.e., on the tenth day, whence only the remaining ten days of zibah need pass before the woman becomes niddah again.');">⁹</span> [if she says,] 'I saw uncleanness for eleven days', her recount commences after nine days; [if she says.] 'I saw uncleanness for twelve days',<span class="x" onmousemove="('comment',' In the case of eleven days, on the same basis, two days of the new zibah period have passed after the intervening days of niddah, so that only the remaining nine days of zibah must be counted before the woman re-enters her niddah period; in the case of a twelve-day flow there are only eight; in the case of a thirteen.day flow only seven days of the zibah period before the new niddah period re-commences. Never earlier than before the passing of seven days, because that is the period necessary for a zibah to become a niddah again, never later than after seventeen days, so that the Mishnaic law becomes evident as indicating the minimum and the maximum necessary for a woman astray in her reckoning before she can definitely reach the 'gate' of her safe reckoning, i.e., the re-commencement of her niddah period.');">¹⁰</span> her re-count commences after eight days;

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