1.
80 (getal)
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80 is the natural number following 79 and preceding 81. 80 is, the sum of Eulers totient function φ over the first sixteen integers, a semiperfect number, since adding up some subsets of its divisors gives 80. Palindromic in bases 3,6,9,15,19 and 39, a repdigit in bases 3,9,15,19 and 39. A Harshad number in bases 2,3,4,5,6,7,9,10,11,13,15 and 16 The Pareto principle states that, for many events, roughly 80% of the effects come from 20% of the causes. Every solvable configuration of the Fifteen puzzle can be solved in no more than 80 single-tile moves, the atomic number of mercury According to Exodus 7,7, Moses was 80 years old when he initially spoke to Pharaoh on behalf of his people. Today,80 years of age is the age limit for cardinals to vote in papal elections. Jerry Rice wore the number 80 for the majority of his NFL career

2.
81 (getal)
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81 is the natural number following 80 and preceding 82. 81 is, the square of 9 and the power of 3. A perfect totient number like all powers of three, the ninth member of the Mian-Chowla sequence. A palindromic number in bases 8 and 26, a Harshad number in bases 2,3,4,7,9,10 and 13. One of three numbers which, when its digits are added together, produces a sum which. The inverse of 81 is 0.012345679 recurring, missing only the digit 8 from the set of digits. This is an example of the rule that, in base b,12 =0. 012 ⋯ ¯, omitting only the digit b−2, messier object M81, a magnitude 8. The duration of Saros series 81 was 1280.1 years, further, the number of lunar eclipse series which began on -0020 February 19 and ended on 1296 April 19. The duration of Saros series 81 was 1316.2 years, eighty-one is also, The number of squares on a shogi playing board The year AD81,81 BC, or 1981. The atomic number of thallium The symbolic number of the Hells Angels Motorcycle Club, H and A are the 8th and 1st letter of the alphabet, respectively. The code for international direct dial phone calls to Japan One of two ISBN Group Identifiers for books published in India Number of stanzas or chapters in the Tao te Ching, Number of prayers said in the Rosary in each night. The 81 is a 1965 song by Candy and the Kisses, artemis 81 is a 1981 BBC TV science fiction drama. The Eighty-One Brothers is a Japanese fable The most points NBA mega-star Kobe Bryant score in a game, the Arabic characters for the numerals 8 and 1 are visible in the left palm of the human hand. In China,81 always reminds people Peoples Liberation Army as it was founded on August 1,81 is used to refer to the motor-club Hells Angels, since H and A are, respectively, the 8th and 1st letters of the alphabet

3.
83 (getal)
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83 is the natural number following 82 and preceding 84. 83 is, the sum of three consecutive primes, the sum of five consecutive primes. The 23rd prime number, following 79 and preceding 89, an Eisenstein prime with no imaginary part and real part of the form 3n −1. The duration of Saros series 83 was 1262.1 years, the Saros number of the lunar eclipse series which began on -197 August 22 and ended on 1318 February. The duration of Saros series 83 was 1514.5 years, when someone reaches 83 they may celebrate a second bar mitzvah M83 is the debut album of the French electronic music group M8383 is a song written by John Mayer in the Room for Squares album. As an example, the television station CIVIC-TV managed by the James Woods character Max Renn in the 1983 film Videodrome was on Channel 83. Eighty-three is also, The year AD83,83 BC, or 1983 The TI-83 series and this symbology is also known to be used by many non-racist Christians and non-denominational Churches. An emoticon based on,3 with wide-open eyes

4.
84 (getal)
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84 is the natural number following 83 and preceding 85. 84 is, the sum of the first seven triangular numbers, a semiperfect number, being thrice a perfect number. A palindromic number and a repdigit in bases 11,13,20,27, the lim sup of the largest finite subgroup of the mapping class group of a genus g surface divided by g. A hepteract is a hypercube with 84 penteract 5-faces. Messier object M84, a magnitude 11, the duration of Saros series 84 was 1280.1 years, and it contained 72 solar eclipses. Further, the number of the lunar eclipse series began on -96 September 13. The duration of Saros series 84 was 1496.5 years, eighty-four is also, The year AD84,84 BC, or 1984. The film 84 Charing Cross Road starring Anne Bancroft and Anthony Hopkins KKNX Radio 84 in Eugene, how many Earth years it takes Uranus to orbit the sun once List of highways numbered 84

5.
89 (getal)
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89 is the natural number following 88 and preceding 90. 89 is, the 24th prime number, following 83 and preceding 97, the smallest Sophie Germain prime to start a Cunningham chain of the first kind of six terms. An Eisenstein prime with no part and real part of the form 3n −1. A Fibonacci number and thus a Fibonacci prime as well, the first few digits of its reciprocal coincide with the Fibonacci sequence due to the identity 189 = ∑ n =1 ∞ F ×10 − =0.011235955 …. A Markov number, appearing in solutions to the Markov Diophantine equation with other odd-indexed Fibonacci numbers, M89 is the 10th Mersenne prime. Although 89 is not a Lychrel number in base 10, it is unusual that it takes 24 iterations of the reverse, among the known non-Lychrel numbers in the first 10000 integers, no other number requires that many or more iterations. The palindrome reached is also unusually large, eighty-nine is, The atomic number of actinium. Messier object M89, a magnitude 11.5 elliptical galaxy in the constellation Virgo, the New General Catalogue object NGC89, a magnitude 13.5 peculiar spiral galaxy in the constellation Phoenix and a member of Roberts Quartet. The Oklahoma Redhawks, an American minor league team, were formerly known as the Oklahoma 89ers. The number alludes to the Land Run of 1889, when the Unassigned Lands of Oklahoma were opened to white settlement, the teams home of Oklahoma City was founded during this event. In Rugby, an 89 or eight-nine move is a following a scrum, in which the number 8 catches the ball. The Elite 89 Award is presented by the U. S. NCAA to the participant in each of the NCAAs 89 championship finals with the highest grade point average. The jersey number 89 has been retired by three National Football League teams in honor of past playing greats, The Baltimore Colts, for Hall of Famer Gino Marchetti, the franchise continues to honor the number in its current identity as the Indianapolis Colts. The Boston Patriots, for Bob Dee, the franchise, now the New England Patriots, continues to honor the number. The Chicago Bears, for Mike Ditka, eighty-nine is also, The designation of Interstate 89, a freeway that runs from New Hampshire to Vermont The designation of U. S. The number of units of each colour in the board game Blokus The number of the French department Yonne Information Is Beautiful cites eighty-nine as one of the words censored on the Chinese internet

6.
90 (getal)
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90 is the natural number preceded by 89 and followed by 91. In English speech, the numbers 90 and 19 are often confused, when carefully enunciated, they differ in which syllable is stressed,19 /naɪnˈtiːn/ vs 90 /ˈnaɪnti/. However, in such as 1999, and when contrasting numbers in the teens and when counting, such as 17,18,19. 90 is, a perfect number because it is the sum of its unitary divisors. A semiperfect number because it is equal to the sum of a subset of its divisors, a Perrin number, preceded in the sequence by 39,51,68. Palindromic and a repdigit in bases 14,17,29, a Harshad number since 90 is divisible by the sum of its base 10 digits. In normal space, the angles of a rectangle measure 90 degrees each. Also, in a triangle, the angle opposing the hypotenuse measures 90 degrees. Thus, an angle measuring 90 degrees is called a right angle, ninety is, the atomic number of thorium, an actinide. As an atomic weight,90 identifies an isotope of strontium, the latitude in degrees of the North and the South geographical poles. NFL, New York Jets Dennis Byrds #90 is retired +90 is the code for international direct dial phone calls to Turkey,90 is the code for the French département Belfort

7.
Natuurlijk getal
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In mathematics, the natural numbers are those used for counting and ordering. In common language, words used for counting are cardinal numbers, texts that exclude zero from the natural numbers sometimes refer to the natural numbers together with zero as the whole numbers, but in other writings, that term is used instead for the integers. These chains of extensions make the natural numbers canonically embedded in the number systems. Properties of the numbers, such as divisibility and the distribution of prime numbers, are studied in number theory. Problems concerning counting and ordering, such as partitioning and enumerations, are studied in combinatorics, the most primitive method of representing a natural number is to put down a mark for each object. Later, a set of objects could be tested for equality, excess or shortage, by striking out a mark, the first major advance in abstraction was the use of numerals to represent numbers. This allowed systems to be developed for recording large numbers, the ancient Egyptians developed a powerful system of numerals with distinct hieroglyphs for 1,10, and all the powers of 10 up to over 1 million. A stone carving from Karnak, dating from around 1500 BC and now at the Louvre in Paris, depicts 276 as 2 hundreds,7 tens, and 6 ones, and similarly for the number 4,622. A much later advance was the development of the idea that 0 can be considered as a number, with its own numeral. The use of a 0 digit in place-value notation dates back as early as 700 BC by the Babylonians, the Olmec and Maya civilizations used 0 as a separate number as early as the 1st century BC, but this usage did not spread beyond Mesoamerica. The use of a numeral 0 in modern times originated with the Indian mathematician Brahmagupta in 628, the first systematic study of numbers as abstractions is usually credited to the Greek philosophers Pythagoras and Archimedes. Some Greek mathematicians treated the number 1 differently than larger numbers, independent studies also occurred at around the same time in India, China, and Mesoamerica. In 19th century Europe, there was mathematical and philosophical discussion about the nature of the natural numbers. A school of Naturalism stated that the numbers were a direct consequence of the human psyche. Henri Poincaré was one of its advocates, as was Leopold Kronecker who summarized God made the integers, in opposition to the Naturalists, the constructivists saw a need to improve the logical rigor in the foundations of mathematics. In the 1860s, Hermann Grassmann suggested a recursive definition for natural numbers thus stating they were not really natural, later, two classes of such formal definitions were constructed, later, they were shown to be equivalent in most practical applications. The second class of definitions was introduced by Giuseppe Peano and is now called Peano arithmetic and it is based on an axiomatization of the properties of ordinal numbers, each natural number has a successor and every non-zero natural number has a unique predecessor. Peano arithmetic is equiconsistent with several systems of set theory

8.
Geheel getal
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An integer is a number that can be written without a fractional component. For example,21,4,0, and −2048 are integers, while 9.75, 5 1⁄2, the set of integers consists of zero, the positive natural numbers, also called whole numbers or counting numbers, and their additive inverses. This is often denoted by a boldface Z or blackboard bold Z standing for the German word Zahlen, ℤ is a subset of the sets of rational and real numbers and, like the natural numbers, is countably infinite. The integers form the smallest group and the smallest ring containing the natural numbers, in algebraic number theory, the integers are sometimes called rational integers to distinguish them from the more general algebraic integers. In fact, the integers are the integers that are also rational numbers. Like the natural numbers, Z is closed under the operations of addition and multiplication, that is, however, with the inclusion of the negative natural numbers, and, importantly,0, Z is also closed under subtraction. The integers form a ring which is the most basic one, in the following sense, for any unital ring. This universal property, namely to be an object in the category of rings. Z is not closed under division, since the quotient of two integers, need not be an integer, although the natural numbers are closed under exponentiation, the integers are not. The following lists some of the properties of addition and multiplication for any integers a, b and c. In the language of algebra, the first five properties listed above for addition say that Z under addition is an abelian group. As a group under addition, Z is a cyclic group, in fact, Z under addition is the only infinite cyclic group, in the sense that any infinite cyclic group is isomorphic to Z. The first four properties listed above for multiplication say that Z under multiplication is a commutative monoid. However, not every integer has an inverse, e. g. there is no integer x such that 2x =1, because the left hand side is even. This means that Z under multiplication is not a group, all the rules from the above property table, except for the last, taken together say that Z together with addition and multiplication is a commutative ring with unity. It is the prototype of all objects of algebraic structure. Only those equalities of expressions are true in Z for all values of variables, note that certain non-zero integers map to zero in certain rings. The lack of zero-divisors in the means that the commutative ring Z is an integral domain

9.
Ordinaalgetal
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In set theory, an ordinal number, or ordinal, is one generalization of the concept of a natural number that is used to describe a way to arrange a collection of objects in order, one after another. Any finite collection of objects can be put in order just by the process of counting, labeling the objects with distinct whole numbers, Ordinal numbers are thus the labels needed to arrange collections of objects in order. An ordinal number is used to describe the type of a well ordered set. Whereas ordinals are useful for ordering the objects in a collection, they are distinct from cardinal numbers, although the distinction between ordinals and cardinals is not always apparent in finite sets, different infinite ordinals can describe the same cardinal. Like other kinds of numbers, ordinals can be added, multiplied, a natural number can be used for two purposes, to describe the size of a set, or to describe the position of an element in a sequence. When restricted to finite sets these two concepts coincide, there is one way to put a finite set into a linear sequence. This is because any set has only one size, there are many nonisomorphic well-orderings of any infinite set. Whereas the notion of number is associated with a set with no particular structure on it. A well-ordered set is an ordered set in which there is no infinite decreasing sequence, equivalently. Ordinals may be used to label the elements of any given well-ordered set and this length is called the order type of the set. Any ordinal is defined by the set of ordinals that precede it, in fact, the most common definition of ordinals identifies each ordinal as the set of ordinals that precede it. For example, the ordinal 42 is the type of the ordinals less than it, i. e. the ordinals from 0 to 41. Conversely, any set of ordinals that is downward-closed—meaning that for any ordinal α in S and any ordinal β < α, β is also in S—is an ordinal. There are infinite ordinals as well, the smallest infinite ordinal is ω, which is the type of the natural numbers. After all of these come ω·2, ω·2+1, ω·2+2, and so on, then ω·3, now the set of ordinals formed in this way must itself have an ordinal associated with it, and that is ω2. Further on, there will be ω3, then ω4, and so on, and ωω, then ωωω, then later ωωωω and this can be continued indefinitely far. The smallest uncountable ordinal is the set of all countable ordinals, in a well-ordered set, every non-empty subset contains a distinct smallest element. Given the axiom of dependent choice, this is equivalent to just saying that the set is ordered and there is no infinite decreasing sequence

10.
Priemfactor
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In number theory, the prime factors of a positive integer are the prime numbers that divide that integer exactly. The prime factorization of an integer is a list of the integers prime factors, together with their multiplicities. The fundamental theorem of arithmetic says that every integer has a single unique prime factorization. To shorten prime factorizations, factors are expressed in powers. For example,360 =2 ×2 ×2 ×3 ×3 ×5 =23 ×32 ×5, in which the factors 2,3 and 5 have multiplicities of 3,2 and 1, respectively. For a prime factor p of n, the multiplicity of p is the largest exponent a for which pa divides n exactly. For a positive n, the number of prime factors of n. Perfect square numbers can be recognized by the fact all of their prime factors have even multiplicities. For example, the number 144 has the prime factors 144 =2 ×2 ×2 ×2 ×3 ×3 =24 ×32. These can be rearranged to make the more visible,144 =2 ×2 ×2 ×2 ×3 ×3 = × =2 =2. Because every prime factor appears a number of times, the original number can be expressed as the square of some smaller number. In the same way, perfect cube numbers will have prime factors whose multiplicities are multiples of three, and so on, positive integers with no prime factors in common are said to be coprime. Two integers a and b can also be defined as if their greatest common divisor gcd =1. Euclids algorithm can be used to determine whether two integers are coprime without knowing their prime factors, the runs in a time that is polynomial in the number of digits involved. The integer 1 is coprime to every integer, including itself. This is because it has no prime factors, it is the empty product and this implies that gcd =1 for any b ≥1. The function, ω, represents the number of prime factors of n, while the function, Ω. If n = ∏ i =1 ω p i α i, for example,24 =23 ×31, so ω =2 and Ω =3 +1 =4