to find percent error you subtract the theoretical (actual) from the experimental, then divide by the theoretical; what you get is a decimal so if you multiply it by 100 you will get the percent
theoretical = 2.0 grams
experimental = 1.65 grams
(1.65 - 2.0) / 1.65 = -0.35/1.65 = -0.21
0.21 x 100 = 21 %
the scale has a 21% probability of being inaccurate
