A measurement is an estimate made with a method and an instrument. Its precision is limited by the instrument’s scale and by how it is used. Reporting many decimal places does not automatically make a result more accurate. Accuracy concerns closeness to a reference or true value; precision concerns consistency or resolution in context. Repeated measurements can reveal variation, but they do not necessarily remove a systematic error such as a ruler with a damaged zero mark. When measuring a book, align the ruler carefully, read from an appropriate angle, and record units. Compare repeated readings and describe the smallest division on the ruler. Avoid adding digits that the method cannot justify. A useful result includes enough information for another person to understand how it was obtained. Practice: Measure one object three times. Record the readings, their spread, and one possible systematic error that repetition alone would not fix.