Descendants of Jacob Through Leah

Genesis 46:15 says, "These are the sons of Leah, whom she bore to Jacob in Paddan-aram, with his daughter Dinah; all his sons and his daughters numbered thirty-three."

If you add up all of the descendants you will actually find them numbering thirty-four.

Why the discrepancy?

At the beginning of the passage in verse eight, Moses writes, "Now these are the names of the sons of Israel, Jacob and his sons, who went to Egypt..."

There is no discrepancy here.

We add them all up and then subtract Er and Onan from the list because they died in Canaan. They never made it to Egypt. Subtracting these two makes the number thirty-two, and then we add one as an unnamed daughter because somewhere in the genealogy there is a girl unmentioned. We know this because verse fifteen says "daughters" plural.