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Hello, Just looking for some feedback. How do you teach percent error? It's not on our book, but when I searched google I get two different methods... Method A % error = (Actual-theoretical)/theoretical x 100 Method B % error = (theoretical-actual)/theoretical x 100 Doesn't method A make more sense so that you get a - percentage if you're below the theoretical? Ex. If I carry out a reaction and get 20 grams, but I calculate I'm supposed to get 25 grams, would it make more sense that my percent error was -20%?

Chris wrote, "[i]Method B % error = (theoretical-actual)/theoretical x 100 Doesn't method A make more sense so that you get a - percentage if you're below the theoretical? Ex. If I carry out a reaction and get 20 grams, but I calculate I'm supposed to get 25 grams, would it make more sense that my percent error was -20%?[/i]" Hi Chris, I have my students use method B, but I do have them note whether they had a higher or lower than expected yield. It sounds like you are doing this by having students do by using Method A. Just make sure your students understand what the negative means...

I've always used Method A.

We just take the absolute value of the equation |(actual-theoretical)/theoretical|x100