U+1D7DB "𝟛" Mathematical Double-Struck Digit Three Unicode Character

U+1D7DB "𝟛" Mathematical Double-Struck Digit Three is a stylized version of the digit three, rendered in a bold, blackboard bold typeface that is commonly used in mathematical notation to denote special sets of numbers. Unlike a standard digit, this double struck variant is part of the Letterlike Symbols block and is specifically intended for use in mathematical contexts, such as representing the number three within abstract algebraic structures or number theory. It maintains the same numeric value as an ordinary three but adds a distinct visual cue to differentiate it from plain text, ensuring clarity in complex formulas.

General Properties

Code Point	U+1D7DB
Version Added	3.1
Name	Mathematical Double-Struck Digit Three
Block	Mathematical Alphanumeric Symbols
General Category	Decimal Number
Canonical Combining Class	Not Reordered
Bidirectional Class	European Number
Decomposition Type	Font
Decomposition Mapping	"3" U+0033 Digit Three

Encodings

HTML Decimal Encoding	𝟛
HTML Hex Encoding	𝟛
UTF-8 Encoding	0xF0 0x9D 0x9F 0x9B
UTF-16 Encoding	0xD835 0xDFDB
UTF-32 Encoding	0x0001D7DB
C/C++/Java Escape	\ud835\udfdb

Unicode Properties

NFC Quick Check	Yes
NFD Quick Check	Yes
Numeric Type	Decimal
Numeric Value	3
Line Break	Numeric
Changes When NFKC Casefolded	Yes
NFKC Casefold	"3" U+0033 Digit Three
NFKC Simple Casefold	"3" U+0033 Digit Three
Script	Common
Script Extensions	Common
Indic Syllabic Category	Other
ID Continue	Yes
XID Continue	Yes
Math	Yes
Other Math	Yes
Vertical Orientation	Rotated
Grapheme Base	Yes
Grapheme Cluster Break	Other
Word Break	Numeric
Sentence Break	Numeric