1. Physical Quantities A quantity is a "physical quantity" if
it expresses the result of a measurement, OR
it expresses the result of a calculation using other physical quantities,
(especially in learning situations) it is presented AS IF it were #1 or #2.

2. Physical Quantities
Communicating the value of a physical quantity requires giving
a number
AND
a unit
an indication of accuracy

3. Accuracy Accuracy can be indicated by
1. words such as "about", "nearly", etc., when the accuracy is not great.
2. +/- notations. (This should be the usual format in laboratory work.)
3. Significant digits