I know the rules to experimental uncertainties with addition and subtraction, but what about division? For instance here The light bulb was measured to have 1.27 ±.05V by the DMM in parallel. Using the DMM in series, its current drawn was .202 ±1A. As a result its resistance was approximately 6.28±.05V/A. I'm not totally sure if I've done it right... Is there any large reference book for all of these rules for future insight?