Being able to describe quantity values and their units is a requirement that is common to many applications in several industrial sectors such as manufacturing, transport and logistics, personal and public health, smart cities, energy, environment, buildings, agriculture. Different ontologies have been developed to describe units, their relations, and quantities with their values. In this paper we propose an alternative approach that leverages the Unified Code of Units of Measure, a code system intended to include all units of measures being contemporarily used in international sciences, engineering, and business. Our approach consists of a main UCUM datatype identified by IRI http://w3id.org/lindt/custom_datatypes#ucum , abbreviated as cdt:ucum . This datatype can be used for lightweight encoding and querying of quantity values, in a wide range of applications where representing and reasoning with quantity kinds and values is more important than reasoning with units. We compare our approach with existing approaches, and demonstrate it with our implementation on top of Apache Jena and an online testing tool.