The sons of Jacob who went to Egypt with him, each with his family, were 1
References for Exodus 1:1
1.1-4 Gn 46.8-27.
Reuben, Simeon, Levi, Judah,
Issachar, Zebulun, Benjamin,
Dan, Naphtali, Gad, and Asher.
The total number of these people directly descended from Jacob was seventy. His son Joseph was already in Egypt.
References for Exodus 1:5
In the course of time Joseph, his brothers, and all the rest of that generation died,