How to quickly insert Double strike or Blackboard bold symbols in Word equations

Word 2016
Double strike or Blackboard bold is a typeface style that is often used for certain symbols in mathematical texts, in which certain lines of the symbol (usually vertical or near-vertical lines) are doubled. The symbols usually denote number sets (see some of usual symbols below).

To type the symbols in Double strike or Blackboard bold in the equation Microsoft Word (to insert equation into your text, click Alt+=), do one of the following:

  • On the Equation tab, in the Symbols group, click the More button:
    More symbols in Word 365

    In the top of list of symbols choose Scripts:

    Scripts in equations Word 365

    In the Scripts list, in the Double-Struck group, choose the symbol you prefer:

Double-Struck in equations Word 365
  • Type \double + capital or lowercase letter:

Capital letters in the Double strike or Blackboard bold:

Symbol Code Description
Double-Struck A in Word 365 \doubleA Represents the algebraic numbers or affine space in algebraic geometry.
Occasionally represents the algebraic numbers, the algebraic closure of Double-Struck Q in Word 365 (more commonly written Double-Struck Q with bar in Word 365 or Double Q with bar in Word 365), or the algebraic integers, an important subring of the algebraic numbers.
Double-Struck B in Word 365 \doubleB Sometimes represents a ball, a Boolean domain, or the Brauer group of a field.
Double-Struck C in Word 365 \doubleC Represents the set of complex numbers.
Double-Struck D in Word 365 \doubleD Represents the unit (open) disk in the complex plane (and by generalisation Double-Struck D in Word 365n may mean the n-dimensional ball) — for example as a model of the Hyperbolic plane. Occasionally Double-Struck D in Word 365 may mean the decimal fractions (see number) or split-complex numbers.
Double-Struck E in Word 365 \doubleE Represents the expected value of a random variable, or Euclidean space, or a field in a tower of fields, or the Eudoxus reals.
Double-Struck F in Word 365 \doubleF Represents a field. Often used for finite fields, with a subscript to indicate the order. Also represents a Hirzebruch surface or a free group, with a subset to indicate the number of generators (or generating set, if infinite).
Double-Struck G in Word 365 \doubleG Represents a Grassmannian or a group, especially an algebraic group.
Double-Struck H in Word 365 \doubleH Represents the quaternions (the H stands for Hamilton), or the upper half-plane, or hyperbolic space, or hyperhomology of a complex.
Double-Struck I in Word 365 \doubleI The closed unit interval or the ideal of polynomials vanishing on a subset. Occasionally the identity mapping on an algebraic structure, or an indicator function, or the set of imaginary numbers (i.e., the set of all real multiples of the imaginary unit, more commonly indicated i Double-Struck R in Word 365).
Double-Struck J in Word 365 \doubleJ Occasionally represents the set of irrational numbers, R\Q ( Double-Struck R in Word 365\ Double-Struck Q in Word 365).
Double-Struck K in Word 365 \doubleK Represents a field, typically a scalar field. This is derived from the German word Körper, which is German for field (literally, "body"; cf. the French term corps). May also be used to denote a compact space.
Double-Struck L in Word 365 \doubleL Represents the Lefschetz motive.
Double-Struck M in Word 365 \doubleM Sometimes represents the monster group. The set of all m-by-n matrices is sometimes denoted Double-Struck M in Word 365(m, n).
Double-Struck N in Word 365 \doubleN Blackboard bold capital N (for natural numbers set).
Double-Struck O in Word 365 \doubleO Represents the octonions.
Double-Struck P in Word 365 \doubleP Represents projective space, the probability of an event, the prime numbers, a power set, the irrational numbers, or a forcing poset.
Double-Struck Q in Word 365 \doubleQ Blackboard bold capital Q (for rational numbers set).
Double-Struck R in Word 365 \doubleR Represents the set of real numbers. R > 0 in Word 365 represents the positive reals, while R >= 0 in Word 365 represents the non-negative real numbers.
Double-Struck S in Word 365 \doubleS Represents a sphere, or the sphere spectrum, or occasionally the sedenions.
Double-Struck T in Word 365 \doubleT Represents the circle group, particularly the unit circle in the complex plane (and Double-Struck T in Word 365n the n-dimensional torus), or a Hecke algebra (Hecke denoted his operators as Tn or Double-Struck T in Word 365), or the tropical semi-ring, or twistor space.
Double-Struck U in Word 365 \doubleU
Double-Struck V in Word 365 \doubleV Represents a vector space or an affine variety generated by a set of polynomials.
Double-Struck W in Word 365 \doubleW Occasionally represents the set of whole numbers (here in the sense of non-negative integers), which also are represented by Double-Struck N in Word 3650.
Double-Struck X in Word 365 \doubleX Occasionally used to denote an arbitrary metric space.
Double-Struck Y in Word 365 \doubleY
Double-Struck Z in Word 365 \doubleZ Represents the set of integers.

Some lowercase letters in the Double strike or Blackboard bold:

Symbol Code Description
Double-Struck a in Word 365 \doublea
Double-Struck b in Word 365 \doubleb
Double-Struck c in Word 365 \doublec
Double-Struck d in Word 365 \doubled May represent the differential symbol.
Double-Struck e in Word 365 \doublee Occasionally used for the mathematical constant e.
Double-Struck f in Word 365 \doublef
Double-Struck g in Word 365 \doubleg
Double-Struck h in Word 365 \doubleh
Double-Struck i in Word 365 \doublei Occasionally used for the imaginary unit.
Double-Struck j in Word 365 \doublej

See also this tip in French: Comment insérer rapidement des symboles double barre ou blackboard gras dans l'équation Word.

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