2 (number) facts for kids
Quick facts for kids



Cardinal  two  
Ordinal  2nd (second / twoth)  
Numeral system  binary  
Factorization  prime  
Gaussian integer factorization  
Prime  1st  
Divisors  1, 2  
Roman numeral  II  
Roman numeral (unicode)  Ⅱ, ⅱ  
Greek prefix  di  
Latin prefix  duo bi  
Old English prefix  twi  
Binary  10_{2}  
Ternary  2_{3}  
Quaternary  2_{4}  
Quinary  2_{5}  
Senary  2_{6}  
Octal  2_{8}  
Duodecimal  2_{12}  
Hexadecimal  2_{16}  
Vigesimal  2_{20}  
Base 36  2_{36}  
Greek numeral  β'  
Arabic  ٢  
Urdu  
Ge'ez  ፪  
Bengali  ২  
Chinese numeral  二，弍，贰，貳  
Devanāgarī  २  
Telugu  ౨  
Tamil  ௨  
Hebrew  ב (Bet)  
Khmer  ២  
Korean  이，둘  
Thai  ๒ 
2 (Two;) is a number, numeral, and glyph. It is the number after 1 (one) and the number before 3 (three). In Roman numerals, it is II.
In mathematics
Two has many meanings in math. For example: . An integer is even if half of it equals an integer. If the last digit of a number is even, then the number is even. This means that if you multiply 2 times anything, it will end in 0, 2, 4, 6, or 8.
Two is the smallest, first, and only even prime number. The next prime number is three. Two and three are the only prime numbers next to each other. The even numbers above two are not prime because they are divisible by 2.
Fractions with 2 in the bottom do not yield infinite.
Two is the framework of the binary system used in computers. The binary way is the simplest system of numbers in which natural numbers (09) can be written.
Two also has the unique property that 2+2 = 2·2 = 2^{2} and 2! + 2 = 2^{2}.
Powers of two are important to computer science.
The square root of two was the first known irrational number.