Question

what does the number of the places after the decimal in a measurement tell you about the precision of the instrument that recorded them?

Answer 1

The more numbers after the decimal point there are, the more precise the instrument which recorded it is. For example, if one instrument during seismic activity records that the magnitude of the earthquake was 2.3, and another instrument recorded that it was 2.3645, the second instrument would have shown to be more precise.