I have to be within 10% (either above or below) 200.59 g. How do I determine how much I can be off?

Question

I'm weighing a project for chemistry (my element is mercury) and I'm currently at 203 g. Is this acceptable within 10% of the 200.59 mass of the element?

Answer 1

10% of 200.59 is 20.059. So add and subtract 20.059 to and from 200.59 to get you acceptable limits. Your 203 is acceptable.