1 (number)
| ||||
|---|---|---|---|---|
| Cardinal | one | |||
| Ordinal | 1st (first) | |||
| Numeral system | unary | |||
| Factorization | 1 | |||
| Divisors | 1 | |||
| Roman numeral | I | |||
| Roman numeral (unicode) | Ⅰ, ⅰ | |||
| Greek prefix | mono- /haplo- | |||
| Latin prefix | uni- | |||
| Binary | 12 | |||
| Ternary | 13 | |||
| Quaternary | 14 | |||
| Quinary | 15 | |||
| Senary | 16 | |||
| Octal | 18 | |||
| Duodecimal | 112 | |||
| Hexadecimal | 116 | |||
| Vigesimal | 120 | |||
| Base 36 | 136 | |||
| Greek numeral | α' | |||
| Persian | ١ - یک | |||
| Arabic | ١ | |||
| Urdu | ||||
| Ge'ez | ፩ | |||
| Bengali & Assamese | ১ | |||
| Chinese numeral | 一,弌,壹 | |||
| Korean | 일, 하나 | |||
| Devanāgarī | १ | |||
| Telugu | ೧ | |||
| Tamil | ௧ | |||
| Kannada | ೧ | |||
| Hebrew | א (alef) | |||
| Khmer | ១ | |||
| Thai | ๑ | |||
| Malayalam | ൧ | |||
One (1) is a natural number after zero and before two. It represents a single item. A human typically has one {head, nose, mouth, and navel (belly-button)}. The Roman numeral is I.
Mathematics[change | change source]
In mathematics, one is also the only number with this special fact: Any number multiplied by 1 equals that number. Then, the number 1 divides any number but it is not divided by any except itself. The number 1 divides any number to give that same number but it cannot be divided by any other number to give one as the answer. Let n be any number. Then n/1 = n but 1/n is never 1 (when n is not 1). Example: 7/1 = 7, but 1/7 is not 1 (it is 0.142857...).
Any number divided by itself always gives 1 as the answer. n/n = 1 (when n is not 0). Example: 7/7 = 1.
0.999... is a repeating decimal that is mathematically equal to 1. Many proofs have been made to show this is correct.
Computer science[change | change source]
The number one is important for computer science because it is, together with zero, a part of the binary numeral system. In machine code and in many programming languages, one means true and zero means false.
Other meanings[change | change source]
- In Germany and Austria, one is the grade for "very good". It is the best grade of six possible grades in Germany and the best of five possible grades in Austria. In the Netherlands, one is the lowest grade, and ten the highest and best. In Poland, one is also the lowest grade, but the highest is six.
- In numerology, the number one is a symbol for everything (unity), the beginning, and God.