This Bible contradiction is from the Skeptic's Annotated Bible.
800,000 for Israel; 500,000 for Judah.
2 Samuel 24:9 View context
And Joab gave up the sum of the number of the people unto the king: and there were in Israel eight hundred thousand valiant men that drew the sword; and the men of Judah [were] five hundred thousand men.
1,100,000 for Israel; 470,000 for Judah.
1 Chronicles 21:5 View context
And Joab gave the sum of the number of the people unto David. And all [they of] Israel were a thousand thousand and an hundred thousand men that drew sword: and Judah [was] four hundred threescore and ten thousand men that drew sword.