10

← 9 10 11 →
← 10 11 12 13 14 15 16 17 18 19 → List of numbers Integers ← 0 10 20 30 40 50 60 70 80 90 →
Cardinal	ten
Ordinal	10th (tenth)
Numeral system	decimal
Factorization	2 × 5
Divisors	1, 2, 5, 10
Greek numeral	Ι´
Roman numeral	X, x
Roman numeral (unicode)	X, x
Greek prefix	deca-/deka-
Latin prefix	deci-
Binary	10102
Ternary	1013
Senary	146
Octal	128
Duodecimal	A12
Hexadecimal	A16
Chinese numeral	十，拾
Hebrew	י (Yod)
Khmer	១០
Armenian	Ժ
Tamil	௰
Thai	๑๐
Devanāgarī	१०
Santali	᱑᱐
Bengali	১০
Arabic & Kurdish & Iranian	١٠
Malayalam	൰
Egyptian hieroglyph	𓎆
Babylonian numeral	𒌋

10 (ten) is the even natural number following 9 and preceding 11. Ten is the base of the decimal numeral system, the most common system of denoting numbers in both spoken and written language.

The number "ten" originates from the Proto-Germanic root "*tehun", which in turn comes from the Proto-Indo-European root "*dekm-", meaning "ten". This root is the source of similar words for "ten" in many other Germanic languages, like Dutch, German, and Swedish. The use of the decimal system is probably because humans have ten fingers and ten toes, which people may have used to count by.

Linguistics

• A collection of ten items (most often ten years) is called a decade.
• The ordinal adjective is decimal; the distributive adjective is denary.
• 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 is to decimate. (In ancient Rome, the killing of one in ten soldiers in a cohort was the punishment for cowardice or mutiny; or, one-tenth of the able-bodied men in a village as a form of retribution, thus causing a labor shortage and threat of starvation in agrarian societies.)

Mathematics

• 10 is a composite number and a happy number.^[1]
• 10 is the smallest noncototient number.^[2]

Decagon

A ten sided polygon is called a decagon.

List of basic calculations

Multiplication	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	20	25	50	100	1000
10 × x	10	20	30	40	50	60	70	80	90	100	110	120	130	140	150	160	200	250	500	1000	10000

Division	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15
10 ÷ x	10	5	3.3	2.5	2	1.6	1.428571	1.25	1.1	1	0.90	0.83	0.769230	0.714285	0.6
x ÷ 10	0.1	0.2	0.3	0.4	0.5	0.6	0.7	0.8	0.9	1	1.1	1.2	1.3	1.4	1.5

Exponentiation	1	2	3	4	5	6	7	8	9	10
10x	10	100	1000	10000	100000	1000000	10000000	100000000	1000000000	10000000000
x10	1	1024	59049	1048576	9765625	60466176	282475249	1073741824	3486784401	10000000000

Science

• The metric system is based on the number 10, so converting units is done by adding or removing zeros (e.g. 1 centimetre = 10 millimetres, 1 decimetre = 10 centimetres, 1 meter = 100 centimetres, 1 dekametre = 10 meters, 1 kilometre = 1,000 meters).
• The 10th element of the periodic table is neon.
• The 10th transition metal is zinc.

Mysticism

In Pythagoreanism, the number 10 played an important role and was symbolized by the tetractys.

See also

• Mathematics portal
• List of highways numbered 10

Notes

References

1. Weisstein, Eric W. "Happy Number". mathworld.wolfram.com.
2. N. J. A. Sloane. "A005278: Noncototients". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.

External links

Wikimedia Commons has media related to 10 (number). Look up ten in Wiktionary, the free dictionary.