A concrete number is a number associated with the things being counted, in contrast to an abstract number
which is a number as a single entity. For example "five apples" and
"half of a pie" are concrete numbers while "five" and "one half" are
abstract numbers. In mathematics the term "number" is usually taken to
mean an abstract number. A denominate number is a type of concrete number with a unit of measure attached with it. For example, 5 inches is a denominate number because it has the unit inches after it.