Jump to navigation Jump to search This article is about the number. For the year, see AD 10. Increasing a quantity by one order of magnitude is most widely understood to mean multiplying the quantity by ten. To reduce something by one tenth $10 valentine gifts for him to decimate.

The number of kingdoms in Five Dynasties and Ten Kingdoms period. The house number of 10 Downing Street. The number of Provinces in Canada. Number of dots in a tetractys. The number of the French department Aube. The number in tarot decks that corresponds to either Chance, Fortune, or the Wheel of Fortune, depending on the deck variant.

Ten is the fifth composite number. Ten is the smallest noncototient, a number that cannot be expressed as the difference between any integer and the total number of coprimes below it. 8 and is accordingly the first discrete semiprime to be in deficit, with all subsequent discrete semiprimes in deficit. While 55 is the tenth triangular number, it is also the tenth Fibonacci number, and the largest such number to also be a triangular number. Ten is the first non-trivial decagonal number, the third centered triangular number and tetrahedral number, and the fifth semi-meandric number.

Ten is the smallest number whose status as a possible friendly number is unknown. There are ten small Pisot numbers that do not exceed the golden ratio. A polygon with ten sides is called a decagon. Petrie polygon of two regular Kepler-Poinsot polyhedra. There are ten regular star polychora in the fourth dimension. Mathieu group which has an irreducible faithful complex representation in 10 dimensions.