13 (عدد): الفرق بين النسختين

|divisor = 1, 13

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'''13''' ('''ثلاثة عشر''') هو [[عدد صحيح]] <ref>{{MathWorld|title=Natural Number|id=NaturalNumber}}</ref><ref>{{Citation| المسار = http://www.merriam-webster.com/dictionary/natural%20number| العنوان = natural number| العمل = Merriam-Webster.com| الناشر = [[ميريام وبستر]]| تاريخ الوصول = 4 October 2014}}

</ref><ref>{{harvtxt|Carothers|2000}} says: "ℕ is the set of natural numbers (positive integers)" (p. 3)</ref><ref name="Mac Lane & Birkhoff 1999 p15">{{harvtxt|Mac Lane|Birkhoff|1999}} include zero in the natural numbers: "Intuitively, the set {{math|ℕ {{=}} {{mset|0, 1, 2, ...}}}} of all "natural numbers" may be described as follows: {{math|ℕ}} contains an "initial" number 0; ...". They follow that with their version of the Peano Postulates. (p. 15)</ref>. يلي العدد [[12 (عدد)|12]] ويسبق العدد [[14 (عدد)|14]] وهو [[عدد طبيعي]] موجب.