The Dewey Decimal System categorizes topics into 10 main classes, with class 300-399 covering the Social Sciences. Topics in this range include sociology (300), economics (330), political science (320), law (340), education (370), and more. This classification system is used in libraries to organize books and other resources by subject.
Arts and Recreation. More information is here: http://en.wikipedia.org/wiki/List_of_Dewey_Decimal_classes#700_.E2.80.93_Arts_and_recreation
It refers to Library books. Certain subjects are listed in a series of numbers & subdivided therein.
All real numbers can be represented in the decimal system. Complex numbers can be represented by a pair of numbers in the decimal system.
In the number system , there are decimal numbers, fractions,rational numbers , irrational numbers , negative and positive numbers.-0.567 on the number system is negative number.
There is no known system for finding prime numbers.
I am not sure what you mean by the number system failing. One possible failure is Godel's incompleteness theorems. According to the first of these, in any consistent system of axioms whose theorems can be listed by an effective procedure is not capable of proving all truths about the arithmetic of the natural numbers. In any such system there will always be statements about the natural numbers that are true, but that are cannot be proved within the system. The second incompleteness theorem, an extension of the first, shows that the system cannot demonstrate its own consistency.
The numbers of wild Asian Elephants range from 30,000 to 53,000. The IUCN Red List population numbers fall within the range (41,410 to 52,345). This wide range seems to depend to a large degree on the system used to count them, or even if a system is used at all. It appears that some systems may be more reliable than others. While the estimated captive numbers are between 14,000 and 15,000. They are listed as "endangered" with the population decreasing by the IUCN Red List. For more information, please see sites listed.
There are an infinite amount of numbers
milk
binaryoctaldecimalhexadecimalRomanHebrewGreeketc.
real numbers
Irrational Numbers, Rational Numbers, Integers, Whole numbers, Natural numbers