18 (eighteen) is the natural number following 17 and preceding 19. It equals ten and eight, twice nine, nine times two or three times six.
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My Favorite Eighteen Blog Posts Of 2008 | I'm Just Sharing
This is a list of my favorite blog posts that I wrote in 2008. ... And now, my favorite eighteen blog posts of 2008, in date order: ...www.imjustsharing.com/my-favorite-eighteen-blog-posts-of-200...Blog Engage - My Favorite Eighteen Blog Posts Of 2008
This is a listing of what I consider as some of my best work on my blog in 2008. ... Login to tell your friends about My Favorite Eighteen Blog Posts Of 2008. ...www.blogengage.com/story.php?title=my-favorite-eighteen-blog...the blog of eviiita Blog | English, baby!
View eighteen's blog at Englishbaby.com, the world's largest social network for English language students. ... eighteen's RSS Feed! Home. English Lessons. Find ...www.englishbaby.com/blog/the_oneGolfing Eighteen Blog
Home | About | Contact | Privacy Policy. Golfing Eighteen Blog. The latest news and products in the world of golf. Wed 31 Dec 2008 ...www.golfingeighteen.com/blog/All Things Eco Blog Carnival Volume Eighteen | Focus Organic.com
All Things Eco Blog Carnival Volume Eighteen. By Stefanie Subscribe via RSS Subscribe via Email ... Let's promote each other, as well as this blog carnival. ...focusorganic.com/eco-blog-carnival-volume-eighteen/18 (eighteen) is the natural number following 17 and preceding 19. It equals ten and eight, twice nine, nine times two or three times six.
In speech, the numbers 18 and 80 are sometimes confused. When carefully enunciated, they differ in which syllable is stressed: 18 vs 80 . However, in dates such as 1864, or when contrasting numbers in the teens, the stress generally shifts to the first syllable: 18 . In some dialects, such as General American, there is little confusion because the single t sound in 80 becomes a d-like flap 1, whereas the double t sound in 18 does not.
In mathematics
Eighteen is a composite number, its proper divisors being 1, 2, 3, 6 and 9. Three of these divisors (3, 6 and 9) add up to 18, hence 18 is a semiperfect number. Eighteen is the first inverted square-prime of the form p.q2.
It is a heptagonal number, and as the sum of the first three pentagonal numbers, it is a pentagonal pyramidal number. It is also the sum of the totient function for the first seven integers.
Eighteen is the second abundant number with the aliquot sum of 21 (117% in abundance) in the aliquot sequence (18,21,11,1,0) thus being the first composite number in the 11-aliquot tree. Eighteen is the aliquot sum of only one number the square 289.
In base 10 it is a Harshad number.
18, aside from 0, is the only number that equals twice the sum of its decimal digits.
In decimals 1.8
In science
- The atomic number of argon
In religion and literature
- The Hebrew word for "life" is חי (chai), which has a numerical value of 18. Consequently, the custom has arisen in Jewish circles to give donations and monetary gifts in multiples of 18 as an expression of blessing for long life.
- In Judaism, in the Talmud; Pirkei Avot (5:25), Rabbi Yehudah ben Teime gives the age of 18 as the appropriate age to get married ("Ben shmonah esra lechupah", at eighteen years old to the Chupah (marriage canopy)). (See Coming of age, Age of majority).
- In Ancient Roman custom the number 18 can symbolise a blood relative.
- Joseph Heller's novel Catch-22 was originally named Catch-18 because of the Hebrew meaning of the number, but was amended to the published title to avoid confusion with another war novel, Mila 18. N James. The Early Composition History of Catch-22. In Biographies of Books: The Compositional Histories of Notable American Writings, J Barbour, T Quirk (edi.) pp. 262-90. Columbia: University of Missouri Press, 1996
- There are 18 chapters in the Bhagavad Gita, which is contained in the Mahabharata, which has 18 books. The Kurukshetra War which the epic depicts, is between 18 armies (11 on the Kuru side, 7 on the Pandava).


























