 One more thing I need to say about significant figures is that errors or uncertainties are only ever given with one significant figure And the measurement that has this uncertainty should have no digits in decimal places smaller than that uncertainty So in our examples here the first one is a good measurement But the second one is not acceptable. In the second example you have to round off the last digit Now remember my example at the beginning of the video. I said I measured my daughter's height as a hundred and thirty nine point seven eight two four centimeters But the uncertainty in this height measurement is really much more like zero point one centimeter So it really only makes sense to write a hundred and thirty nine point eight plus or minus point one centimeters