Copy ℚ, the set of rational numbers symbol, to paste, or ℝ, ℤ, ℕ and ℂ and forms like ℤ⁺.
Set of Rational Numbers Symbol
ℚDouble-struck capital QU+211AReady to copy
19 number set symbols. Tap any value to copy it.
19 number set symbols. A character and its name both copy the character. A code copies the code.
Character
Name
Code point
HTML
U+211A. The set of rational numbers, the fractions of two integers; the Q stands for quotient. No key and no Alt code. ℚ or ℚ in HTML.
U+211D. All real numbers as one set. In HTML it is ℝ, or ℝ by its second name.
U+2124. The integers. The letter is for the German Zahl, number. ℤ or ℤ in HTML.
U+2115. The natural numbers, which may or may not include zero, depending on the author. ℕ or ℕ.
U+2102. The complex numbers. ℂ or ℂ in a web page.
The real numbers with the rational ones taken away, written with the set minus sign: the irrational numbers.
A small plus at the top right of the letter keeps only 1, 2, 3 and so on.
Read aloud: x is in R. It says that x may be any number on the number line.
U+210D. The quaternions; the H honors Hamilton, who described them. ℍ or ℍ.
U+2119. A letter of several jobs: the prime numbers, projective space, the probability of an event, at times the irrational numbers. ℙ or ℙ.
The same set with the plus written low, as some authors prefer.
A small 0 after the letter says that counting starts at nothing.
With a subscript one instead, the set that begins at 1.
With a prime p written low after it, the letter means the field of p-adic numbers.
With a positive integer n written low, it can mean arithmetic modulo n.
A double-struck F stands for a field, and a subscript gives the order of a finite one.
The letter under a bar: the usual way to write the algebraic closure of the rationals, the algebraic numbers.
The same statement for the integers, as when a domain is given.
Here the slash through ∈ turns the statement around: x cannot be written as a fraction of two integers.
The set of rational numbers symbol is ℚ, a double-struck capital Q, U+211A; the Q stands for quotient. The all real numbers symbol is ℝ, the integers are ℤ, the natural numbers ℕ and the complex numbers ℂ.
Read the full guide
Typing the number set symbols
None of these letters is on a keyboard or in an Alt code table, so the real number symbol and its relatives are copied. In HTML, ℝ is ℝ or ℝ, ℚ is ℚ and ℤ is ℤ. LaTeX writes them \mathbb{R}, \mathbb{Q} and \mathbb{Z}, with the amssymb package.
Sets built from them
The irrational numbers can be written ℝ∖ℚ, the reals without the rationals. ℤ⁺ is the positive integer symbol, the set that starts at 1, and ℕ₀ is the natural numbers with zero.
When no real number solves an equation, the solution set is the empty set, ∅.
To give a domain, write the set after ∈: x ∈ ℤ for an integer.
ℂ, ℚ, ℝ and ℤ are nearly universal in meaning, so discrete math reads them the same way.
Questions and answers
What is the symbol for all real numbers?
ℝ, a double-struck capital R, U+211D, which stands for the set of all real numbers. That x is any real number is written x ∈ ℝ.
How do I write that x equals all real numbers?
With the element sign: x ∈ ℝ, read x is an element of the real numbers. The sign ∈ is U+2208, and the set comes after it.
Is there an Alt code for the real number or integer symbol?
No. Neither Alt code table holds ℝ, ℤ, ℕ or ℚ: no double-struck N, R, Z or I has a code. In HTML they are ℝ, ℤ, ℕ and ℚ, and 𝕀 is 𝕀.
What is the symbol for natural numbers and integers?
ℕ is the natural number symbol and ℤ the integer symbol in math; the Z is for the German word Zahl, number. ℕ may or may not include zero, so ℕ₀ and ℤ⁺ are written to be exact.
How is the rational numbers symbol handwritten?
As a capital Q with certain strokes doubled. The style, called blackboard bold, began as the way to write bold letters by hand on a blackboard, and print took it over as double-struck type.
All 19 number set symbols
Start here 8
ℂDouble-struck capital CU+2102. The complex numbers. ℂ or ℂ in a web page.
ℕDouble-struck capital NU+2115. The natural numbers, which may or may not include zero, depending on the author. ℕ or ℕ.
ℚDouble-struck capital QU+211A. The set of rational numbers, the fractions of two integers; the Q stands for quotient. No key and no Alt code. ℚ or ℚ in HTML.
ℝDouble-struck capital RU+211D. All real numbers as one set. In HTML it is ℝ, or ℝ by its second name.
ℤDouble-struck capital ZU+2124. The integers. The letter is for the German Zahl, number. ℤ or ℤ in HTML.
ℝ∖ℚIrrational numbersThe real numbers with the rational ones taken away, written with the set minus sign: the irrational numbers.
ℤ⁺Positive integersA small plus at the top right of the letter keeps only 1, 2, 3 and so on.
x∈ℝX is a real numberRead aloud: x is in R. It says that x may be any number on the number line.
Show all 19 number set symbols (11 more)
Sets of numbers 2
ℍDouble-struck capital HU+210D. The quaternions; the H honors Hamilton, who described them. ℍ or ℍ.
ℙDouble-struck capital PU+2119. A letter of several jobs: the prime numbers, projective space, the probability of an event, at times the irrational numbers. ℙ or ℙ.
With a sign or an index 7
ℚ̅Algebraic numbersThe letter under a bar: the usual way to write the algebraic closure of the rationals, the algebraic numbers.
𝔽ₚFinite fieldA double-struck F stands for a field, and a subscript gives the order of a finite one.
ℤₙIntegers modulo nWith a positive integer n written low, it can mean arithmetic modulo n.
ℕ₁Natural numbers from oneWith a subscript one instead, the set that begins at 1.
ℕ₀Natural numbers with zeroA small 0 after the letter says that counting starts at nothing.
ℚₚP-adic numbersWith a prime p written low after it, the letter means the field of p-adic numbers.
ℤ₊Positive integers, plus belowThe same set with the plus written low, as some authors prefer.
In a statement 2
x∈ℤX is an integerThe same statement for the integers, as when a domain is given.
x∉ℚX is not rationalHere the slash through ∈ turns the statement around: x cannot be written as a fraction of two integers.