Rabbi Chiya bar Abba said: Why were the years of Yishmael enumerated? In order to calculate from them the years of Yaakov…
On the daf / in context: The precise lifespan of Yishmael supplies the chronological hinge needed to determine Yaakov’s age when he left home and spent time learning in the academy of Ever.
Type of Learning
Custom (Bavli — chronology for Yaakov’s Torah study)
What Is Learned
The years of Yishmael are recorded so that Yaakov’s age and the period he spent studying Torah with Ever can be calculated.