practical number
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Practical number — In mathematics, and in particular number theory, a practical number or panarithmic number is a positive integer n such that all smaller positive integers can be represented as sums of distinct divisors of n . For example, 12 is a practical number … Wikipedia
Practical Kabbalah — (Heb. Kabbalah Ma asit ) is a branch of Kabbalah which concerns the use of magic. Its teachings include the use of Divine and angelic names for amulets and incantations.Elber, Mark. The Everything Kabbalah Book: Explore This Mystical Tradition… … Wikipedia
Practical joke — involving completely blocking someone s doorway with phone books … Wikipedia
Practical Ethics — is an introduction to applied ethics by modern bioethical philosopher Peter Singer. It was published in 1979 and has since been translated into a number of languages, causing outrage in Germany, Austria and Switzerland.The work analyzes, in… … Wikipedia
number game — Introduction any of various puzzles and games that involve aspects of mathematics. Mathematical recreations comprise puzzles and games that vary from naive amusements to sophisticated problems, some of which have never been solved.… … Universalium
Practical Mechanics — Infobox Magazine title = Practical Mechanics image size = 250px image caption = Cover to Practical Mechanics , The Car Any Amateur Can Make! publisher = category = Science and technology magazines total circulation = circulation year = frequency … Wikipedia
Number theory — A Lehmer sieve an analog computer once used for finding primes and solving simple diophantine equations. Number theory is a branch of pure mathematics devoted primarily to the study of the integers. Number theorists study prime numbers (the… … Wikipedia
number symbolism — Introduction cultural associations, including religious, philosophic, and aesthetic, with various numbers. Humanity has had a love hate relationship with numbers from the earliest times. Bones dating from perhaps 30,000 years ago show … Universalium
Number system — This article is about different sets of numbers. For different methods of expressing numbers with symbols, see numeral system. In mathematics, a number system is a set of numbers, (in the broadest sense of the word), together with one or more… … Wikipedia
Number density — In physics, astronomy, and chemistry, number density (symbol: n) is an intensive quantity used to describe the degree of concentration of countable objects (particles, molecules, phonons, galaxies, etc.) in the three dimensional physical space.… … Wikipedia
