The CLDT magnitude classes are Association, Character, Date, Float, Fraction, Integer, and Time. Magnitude classes represent objects to which a linear ordering can be applied, such as characters, numbers, dates, and times. Magnitude classes support the capability to compare, query, and determine ranges of these ordered objects.

A ScaledDecimal class also exists, and DM is its application. Although not technically part of CLDT, the ScaledDecimal class is associated with the magnitude classes of CLDT. Unlike the Float class, the ScaledDecimal class is used for exact representation of real numbers so that there is no round-off error.

Numbers are a major subset of the magnitude classes. The different number classes (Float, Fraction, and Integer) provide concrete representations for integer, rational, and real numbers. Numbers can only be created by the evaluation of an expression or by literal declaration.

All of the magnitude classes support the basic magnitude protocol for comparing values.