Final zeros to the right of the decimal point are considered significant. What do those zeros indicate and why are they significant? For example, in 2.000 there are four significant figures.
"$2.000$" does not mean $2.000 \pm 0.0005$.
"$2.000$" does not mean the interval [1.9995,2.0005].
"2.000" means that there is an unspecified amount of uncertainty in at least the last, and possibly the last two digits.
The correction for a weight is computed to be 285.41 mg and the uncertainty is 33.4875 mg. First, round the uncertainty to two significant figures, that is 33 mg. Then, round the correction to the same number of decimal places as the uncertainty statement, that is, 285 mg
So in other words, for people who follow the NIST standard of stating uncertainty to two significant digits:
2.000 can mean anything from 1.990-2.010 to 1.901-2.099
Others only express uncertainty using one significant digit, in which case:
2.000 can mean anything from 1.999-2.001 to 1.991-2.009
The zeros to the right of the decimal point denotes the expected precision of a measurement.
Thus a value of 2.0 indicates that the the measurement falls in the interval [1.95,2.05[. The value 2.00 correspond to the interval [1.995,2.005[ and 2.000 corrospond to the interval [1.9995,2.0005[.
Therefore the amount of zeros are significant for indicating the precision of a measurement.
I think it's worth noting that the number of 0s is not guaranteed to indicate significance/precision, as it's possible the author did not follow standard conventions. For instance, they might have reported the number of digits that some measurement device displays, which may or may not correlate with the overall measurement precision in the context of the particular experiment. When in doubt, look for a discussion of the context of the measurement and an analysis of possible errors; if that's not present, consider asking the author to confirm whether they did, in fact, mean for the number of digits to reflect the precision.