Explains the significance of the mole as a unit of measure by showing the relationship between physical quantities and their mathematical representations. Offers a summary of the principles of metrology that make creation of physical quantities and units seem reasonable. A table of base physical quantities and units is included. (RT)

Proposes a method for dealing with units that require involvement of units of each physical quantity at every stage of a calculation. Preliminary ideas on algebra and the concept of a physical quantity, equations relating two or more units, calculations of physical quantities, and logarithms are considered. (JM)