Today's daf is sponsored by Sarah Robinson in memory of her father Moshe Nachum ben Chana Leiba v'Yaakov z"l. The gemara explains how Rabbi Yosi and the rabbis came to different dates regarding when the Torah was given and as a result a different number of days that spouses needed to separate. Several sources are brought either against Rabbi Yosi or against the rabbis and are then explained. According to Rabbi Yosi, one needs to explain that God told Moshe two days of separation but Moshe added a third and God agreed with him. There are two other cases brought where Moshe initiated something and God agreed. What are different opinions regarding what Moshe did the first three days upon arriving at Mount Sinai? Did he first teach them about the punishments, then the rewards or the reverse? What were they commanded about Shabbat in Marah - also techumin or everything except that? This affects whether or not they travelled on shabbat and arrived on Sunday or travelled and arrived on Sunday. The gemara gets into the counts of what day of the week did they leave Egypt and how many days were in Nissan and Iyar of that year and how one can arrive at the different opinions of rabbi Yosi adn the rabbis. Does the days of the week of Rosh Chodesh Sivan according to Rabbi Yosi and the rabbis fit in with a braita that explains the dates in the following year when the tabernacle was put up?