10 is an evennatural number following 9 and preceding 11. Ten is the base of the decimal numeral system, by far the most common system of denoting numbers in both spoken and written language. The reason for the choice of ten is assumed to be that humans have ten fingers.
The number in tarot decks that corresponds to either Chance, Fortune, or the Wheel of Fortune, depending on the deck variant.
In mathematics
Ten is a composite number with 4 divisors, its proper divisors being, and. 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.
Ten is the second discrete semiprime and the second member of the discrete semiprime family. Ten has an aliquot sum σ of 8 and is accordingly the first discrete semiprime to be in deficit. All subsequent discrete semiprimes are in deficit. The aliquot sequence for 10 comprises five members with this number being the second composite member of the 7-aliquot tree.
Ten is the smallest semiprime that is the sum of all the distinct prime numbers from its lower factor through its higher factor Only three other small semiprimes share this attribute.
Ten is the sum of the first three prime numbers, of the four first positive integers, of the square of the two first odd numbers and also of the first four factorials. Ten is the eighth Perrin number, preceded in the sequence by 5, 5, 7.
As is the case for any base in its system, ten is the first two-digit number in decimal and thus the lowest number where the position of a numeral affects its value. Any integer written in the decimal system can be multiplied by ten by adding a zero to the end.
Roman numerals
The Roman numeral for ten is X ; it is thought that the V for five is derived from an open hand, and X for ten from both hands. Incidentally, the Chinese word numeral for ten, is also a cross: wikt:十.
Positional numeral systems other than decimal
The digit '1' followed by '0' is how the value of p is written in base p.
Base
Numeral system
Number
1
unary
**********
2
binary
1010
3
ternary
101
4
quaternary
22
5
quinary
20
6
senary
14
7
septenary
13
8
octal
12
9
novenary
11
10
decimal
10
12
duodecimal
X
16
hexadecimal
A
List of basic calculations
Multiplication
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
25
50
100
1000
10 × x
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
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.
2.5
2
1.
1.
1.25
1.
1
0.
0.8
0.
0.
0.
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
10
10
100
1000
10000
100000
1000000
10000000
100000000
1000000000
10000000000
x
1
1024
59049
1048576
9765625
60466176
282475249
1073741824
3486784401
10000000000
In science
The SI prefix for 10 is "deca-". The meaning "10" is part of the following terms:
* People traditionally tithed one-tenth of their produce. The practice of tithing is still common in Christian churches today, though it is disputed in some circles as to whether or not it is required of Christians.
* In Deuteronomy 26:12, the Torah commands Jews to give one-tenth of their produce to the poor. From this verse and from an earlier verse there derives a practice for Jews to give one-tenth of all earnings to the poor.
* Interpretations of Genesis in Talmudic and Midrashic teachings suggest that on the first day, God drew forth ten primal elements from the abyss in order to construct all of Creation: Heaven, Earth, Chaos, Void, Light, Darkness, Wind, Water, Day, and Night. See also Bereshit.
Most countries issue coins and bills with a denomination of 10. Of these, the U.S. dime, with the value of ten cents, or one tenth of a dollar, derives its name from the meaning "one-tenth" − see Dime #Denomination history and etymology.
In music
The interval of a major tenth is an octave plus a major third.
The interval of a minor tenth is an octave plus a minor third.
"Ten lords a-leaping" is the gift on the tenth day of Christmas in the carol "The Twelve Days of Christmas".
In association football, the number 10 is traditionally worn by the team's advanced playmaker. This use has led to "Number 10" becoming a synonym for the player in that particular role, even if he or she does not wear that number.
In gridiron football, a team has a limited number of downs to advance the ball ten yards or more from where it was on its last first down; doing this is referred to as gaining another first down.
In auto racing, driving a car at ten-tenths is driving as fast as possible, on the limit.
In basketball, each quarter runs for 10 minutes under FIBA, WNBA, and NCAA women's rules.
In blackjack, the Ten, Jack, Queen and King are all worth 10 points.
In boxing, if the referee counts to 10 whether the boxer is unconscious or not, it will declare a winner by knockout.
In cricket, a team's innings ends once it has lost 10 wickets.
In men's field lacrosse, each team has 10 players on the field at any given time, except in penalty situations.
In most rugby league competitions, the number 10 is worn by one of the two starting props. One exception to this rule is the Super League, which uses static squad numbering.
In rugby union, the starting fly-half wears the 10 shirt.
In ten-pin bowling, 10 pins are arranged in a triangular pattern and there are 10 frames per game.
The traditional Snellen chart uses 10 different letters.
Ten is an Australian television network. The Sydney member of the network has the three-letter call-sign TEN and used to broadcast in analogue on VHF Channel 10.
Number Ten is a character in the book series Lorien Legacies. The sixth book, The Fate of Ten, is named after her.
A Cartoon Network franchise Ben 10, which has a number on its title.
