People are rarely truly “wrong”; more often, they’re just speaking from a limited perspective. If you want to change their mind, don’t flat-out deny what they’re saying, instead, add new information.

When someone insists on a point, they’re probably right in some sense. They’re telling you that 3+2=5, and of course, it does. What they may not see is that the problem also includes a 4, which makes the full answer 9. So instead of telling them they’re wrong for saying the answer is 5, just show them the missing piece.