# Double-Struck Capital Q ℚ

## Symbol Meaning

The set of rational numbers ℚ = {m/n} consists of numbers that can be expressed as ordinary fractions (for example, 4/3). In decimal representation, they can be finite or repeating decimals, such as 4/3 = 1.333... The term “rational” comes from the Latin word “quotient”, which furthermore developed in English. It's interesting enough that the set ℚ is also countable (equivalent in cardinality to the set of natural numbers ℕ).

The sets ℕ, ℤ, ℚ, ℝ, ℂ are often written in bold font (for example, in the works of Nicolas Bourbaki) or as double-struck letters on blackboards and manuscripts. The usage of double-struck font in printed texts was introduced by American mathematicians and became widespread with the famous textbook on complex analysis by Gunning and Rossi, published in 1965.

The symbol “Double-Struck Capital Q” is included in the “Letterlike symbols” subblock of the “Letterlike Symbols” block and was approved as part of Unicode version 1.1 in 1993.

Text is also available in the following languages: Español; Русский;

### Synonyms

the set of rational numbers.

Unicode Name | Double-Struck Capital Q |

Unicode Number | |

HTML Code | |

CSS Code | |

Entity | ℚ |

Unicode Block | Letterlike Symbols |

Unicode Subblock | Letterlike symbols |

Unicode Version | 1.1 (1993) |

Version | 1.1 |

Block | Letterlike Symbols |

Type of paired mirror bracket (bidi) | None |

Composition Exclusion | No |

Case change | 211A |

Simple case change | 211A |

Math | + |

Alphabetic | + |

Uppercase | + |

Cased | + |

ID_Start | + |

ID_Continue | + |

XID_Start | + |

XID_Continue | + |

Grapheme_Base | + |

age | 1.1 |

scripts | Common |

Encoding | hex | dec (bytes) | dec | binary |
---|---|---|---|---|

UTF-8 | E2 84 9A | 226 132 154 | 14845082 | 11100010 10000100 10011010 |

UTF-16BE | 21 1A | 33 26 | 8474 | 00100001 00011010 |

UTF-16LE | 1A 21 | 26 33 | 6689 | 00011010 00100001 |

UTF-32BE | 00 00 21 1A | 0 0 33 26 | 8474 | 00000000 00000000 00100001 00011010 |

UTF-32LE | 1A 21 00 00 | 26 33 0 0 | 438370304 | 00011010 00100001 00000000 00000000 |