This Bible contradiction is from the Skeptic's Annotated Bible.
Genesis 46:27 View context
And the sons of Joseph, which were born him in Egypt, [were] two souls: all the souls of the house of Jacob, which came into Egypt, [were] threescore and ten.
Exodus 1:5 View context
And all the souls that came out of the loins of Jacob were seventy souls: for Joseph was in Egypt [already].
Acts 7:14 View context
Then sent Joseph, and called his father Jacob to [him], and all his kindred, threescore and fifteen souls.