based on an earlier version of the Wolfram Language.
Mathematica 9 extends its symbolic programming paradigm to support units, allowing a wide range of computations to be carried out with a sophisticated unit system. It provides unique syntax-free linguistic input to support the entry and discovery of units.
Quantity — represents a value associated with a unit
UnitConvert — convert between different units and unit systems
QuantityMagnitude — give the value associated with a quantity
QuantityUnit — give the unit associated with a quantity
CompatibleUnitQ — test whether multiple quantities are compatible
CommonUnits — convert a list of quantities to a common unit
UnitSimplify — convert to simpler units
StringRotateLeft — cycles the characters in a string to the left
StringRotateRight — cycles the characters in a string to the right