Rashi points out an interesting difficulty in calculating a timeline for the life of Yaakov. (Rashi on Breishis 28:9) Here are some questions to clarify the issue.
Yaakov (Jacob) was 130 years old and Yosef (Joseph) was 39 years old when Yaakov and his family came to Egypt and stood before Pharaoh [Bereishis (Genesis) 47:9, 41:46, 45:11]. Yaakov left Lavan’s house when Yosef was 6 years old [Bereishis 30:25, 31:41].
A. How old was Yaakov when he finished working for Lavan?
130 – 39 = 91 years age difference
Yaakov was 130 when Yosef was 39. So Yaakov was 91 when Yosef was born.
91 + 6 = 97 years age at the time
If Yosef was 6 then Yaakov had to be 97 years old
B. Yaakov worked for 20 years in Lavan’s household. How old was he when he arrived at Lavan’s house? (Breishis 31:41)
97 – 20 = 77 years old when he left Lavan’s house
C. Yishmael (Ishmael) was born to Avraham (Abraham) when he was 86 years old. Avraham performed the Bris Milah (circumcision) on Yishmael when Avraham was 99 years old [Bereishis (Genesis) 16:16, 17:24]. How old was Yishmael when he received Bris Milah?
99 years – 86 years = 13 years
D. Yishmael (Ishmael) was 14 years old when Yitzchak (Isaac) was born [Bereishis (Genesis) 17:25, 18:10]. Yaakov (Jacob) was born to Yitzchak when Yitzchak was 60 years old [Bereishis 25:26]. How old was Yishmael when Yaakov was born?
14 + 60 = 74 years
Yishmael lived to 137 [Bereishis 25:17]. How old was Yaakov when Yishmael died?
137 – 74 = 63 years old
E. Yaakov left his father’s home at the same time his uncle, Yishmael, died. This now creates a problem. We know that Yaakov left his father’s house at the age of 63, but he did not get to the house of Lavan until he was 77. Our sages explain that after Yaakov left his father’s home he went the school of Shem (Noah’s son) and Ever (Shem’s grandson). He stayed there until he went to the house of Lavan [Megillah 16b]. Based on the answers above, how many years did he stay at the school of Shem and Ever?
He was a Lavan’s house until the age of 77 – 63 = 14 years.