In The Romance Resonance he read a data table in a text book wrong
Sheldon: This is the very copy of The Handbook of Chemistry and Physics in which I looked up the reaction rates of mendelevium and…
Amy: And what?
Sheldon: No. No, no, no, no.
Amy: What’s wrong?
Sheldon: I’ve made a horrible mistake.
Amy: What are you talking about?
Sheldon: This table, it’s in square centimetres. I read it as square metres. You know what that means?
Amy: That Americans can’t handle the metric system?
Sheldon: Amy, I was off by a factor of 10,000.