Except Math Symbol

Copy ∖, the math symbol for except, or a ready string such as ℝ∖{0}, every real number except zero.

Except Math Symbol

∖Set minusU+2216Ready to copy

32 signs and strings. Tap any value to copy it.

32 signs and strings. A character and its name both copy the character. A code copies the code.
Character	Name	Code point	Alt code	Option keys	HTML	LaTeX
	U+2216. The sign of the set difference: A ∖ B is everything in A except what is also in B. &setminus; in HTML, \setminus in LaTeX.
	A, U+2216, B: the elements of A that are not in B. Put your own two sets in place of the letters.
	ℝ, U+2216 and a 0 in braces: every real number except zero. Another number in the braces leaves that one out.
	U+2209. One thing left out of a set: x ∉ A says that x is not in A. ∉ in HTML, \notin in LaTeX.
	U+2260. Leaves one value out of a condition: x ≠ 0 is every x except 0. Option+= on a U.S. keyboard, ≠ in HTML, \ne in LaTeX.
	U+2201. Everything that is not in a set: ∁A is the complement of A. &comp; in HTML; \complement in LaTeX needs the amssymb package.
	The same pattern with ℤ: every integer except 0.
	The real numbers without the rational ones. What remains is the set of irrationals.
	Everything in the universe U that is not in A: the complement of A written as a difference.
	The same set as A ∖ B: what A shares with the complement of B. The raised c is U+1D9C.
	The statement that one thing, x, is left out of the set A.
	Every value of x except 0.
	U+2212. Some books write the set difference with it, A − B, which can also be read as every a − b; the standard sign is ∖. − in HTML.
	A ∖ B spelled with the minus sign, U+2212, as some books do.
	A with a raised c, U+1D9C: the usual way to write everything that is not in A.
	A and the prime, U+2032: another way to write the complement of A.
	U+2284. A ⊄ B: the set A is not wholly inside B. &nsub; in HTML.
	U+222A. A ∪ B is everything that is in A, in B or in both. ∪ in HTML, \cup in LaTeX.
	U+2229. A ∩ B is what the two sets share. Alt+239, ∩ in HTML, \cap in LaTeX.
	U+2206. Unicode lists symmetric difference among its uses: A ∆ B is what is in exactly one of the two sets. Option+J on a U.S. keyboard.
	U+2296. Unicode's other name for it is symmetric difference: A ⊖ B is the same set as A ∆ B. &ominus; in HTML, \ominus in LaTeX.
	Square brackets include both endpoints: every number from a to b, a and b among them.
	Round brackets leave both endpoints out: the numbers between a and b, not including a or b.
	From a up to but not including b: a is in, b is not.
	Not including a, up to and including b.
	The same interval as [a,b): a bracket turned outward marks the endpoint that is left out.
	U+005C. The backslash of the keyboard. Unicode cross-refers it to set minus and keeps the two apart. \ in HTML, \backslash in LaTeX.
	U+29F5. A backslash made to be a math operator, in Unicode since version 3.2 (2002).
	U+29F9. A taller stroke. Unicode's other name for it is z notation schema hiding.
	U+27CD. A longer diagonal that Unicode cross-refers to set minus, added in version 6.1 (2012). \diagdown in LaTeX, with the amssymb package.
	U+FE68. The backslash in a small form, from the block Small Form Variants.
	U+FF3C. The backslash in its fullwidth form, from the block Halfwidth and Fullwidth Forms.

Next step ℕ, ℚ and ℂ in double-struck ∀ and ∃ among the other math signs

How it works

In math, except is written ∖, Set minus, U+2216: A ∖ B is everything in A that is not in B. It is a character of its own, not the backslash key. A web page writes &setminus; and LaTeX \setminus.

Read the full guide

Excluding a number or a whole set

ℝ∖{0} is the real numbers excluding zero: the braces make a set of the 0, and ∖ takes that set away. ℝ∖ℚ leaves the irrational numbers. Discrete math, which covers set theory, calls A ∖ B the set difference. The standard ISO 31-11 writes it with ∖; some books write A − B, which can also mean every a − b.

Including and not including an endpoint

For a range, the brackets say it. A square bracket means including the endpoint and a round one not including it: [2,5) runs from 2 up to but not including 5. Another notation turns the bracket outward instead: [2,5[.

x ≠ 0 leaves out a single value with no set notation at all.
A ∖ B is the same set as A ∩ Bᶜ, A cut down to the complement of B.

Questions and answers

What is the math symbol for excluding?

∖, the set minus sign. The set to keep goes on its left and what to exclude on its right: ℤ∖{0} is every integer excluding zero, and {1,2,3}∖{2,3,4} is {1}.

Which symbol means not include in discrete math?

It depends on what is left out. A ∖ B does not include the members of B. x ∉ A says that one thing is not in A. A ⊄ B says that the set A is not wholly inside B.

How do union, intersection and except differ?

A ∪ B, the union, is everything in either set. A ∩ B, the intersection, is what both share. A ∖ B, the except or difference, is what A has and B does not.

Is the except symbol the same as a backslash?

No. The backslash is U+005C, a key on the keyboard; set minus is U+2216, a math operator. LaTeX has both: \setminus draws the stroke of \backslash with a little more space on each side, and the amssymb package adds \smallsetminus.

All 32 signs and strings

Start here 6

A without B A, U+2216, B: the elements of A that are not in B. Put your own two sets in place of the letters.
All real numbers except zero ℝ, U+2216 and a 0 in braces: every real number except zero. Another number in the braces leaves that one out.
Complement U+2201. Everything that is not in a set: ∁A is the complement of A. &comp; in HTML; \complement in LaTeX needs the amssymb package.
Not an element of U+2209. One thing left out of a set: x ∉ A says that x is not in A. ∉ in HTML, \notin in LaTeX.
Not equal to U+2260. Leaves one value out of a condition: x ≠ 0 is every x except 0. Option+= on a U.S. keyboard, ≠ in HTML, \ne in LaTeX.
Set minus U+2216. The sign of the set difference: A ∖ B is everything in A except what is also in B. &setminus; in HTML, \setminus in LaTeX.

Show all 32 signs and strings (26 more)

Ready to edit 6

All integers except zero The same pattern with ℤ: every integer except 0.
Complement of A in U Everything in the universe U that is not in A: the complement of A written as a difference.
Difference written as an intersection The same set as A ∖ B: what A shares with the complement of B. The raised c is U+1D9C.
The irrational numbers The real numbers without the rational ones. What remains is the set of irrationals.
x is not in A The statement that one thing, x, is left out of the set A.
x is not zero Every value of x except 0.

Other signs 5

Complement of A A with a raised c, U+1D9C: the usual way to write everything that is not in A.
Complement of A, with a prime A and the prime, U+2032: another way to write the complement of A.
Difference with a minus sign A ∖ B spelled with the minus sign, U+2212, as some books do.
Minus sign U+2212. Some books write the set difference with it, A − B, which can also be read as every a − b; the standard sign is ∖. − in HTML.
Not a subset of U+2284. A ⊄ B: the set A is not wholly inside B. &nsub; in HTML.

Union and intersection 4

Circled minus U+2296. Unicode's other name for it is symmetric difference: A ⊖ B is the same set as A ∆ B. &ominus; in HTML, \ominus in LaTeX.
Increment U+2206. Unicode lists symmetric difference among its uses: A ∆ B is what is in exactly one of the two sets. Option+J on a U.S. keyboard.
Intersection U+2229. A ∩ B is what the two sets share. Alt+239, ∩ in HTML, \cap in LaTeX.
Union U+222A. A ∪ B is everything that is in A, in B or in both. ∪ in HTML, \cup in LaTeX.

Including or not 5

Closed interval Square brackets include both endpoints: every number from a to b, a and b among them.
Half-open interval, a left out Not including a, up to and including b.
Half-open interval, b left out From a up to but not including b: a is in, b is not.
Interval with a reversed bracket The same interval as [a,b): a bracket turned outward marks the endpoint that is left out.
Open interval Round brackets leave both endpoints out: the numbers between a and b, not including a or b.

Backslashes 6

Big reverse solidus U+29F9. A taller stroke. Unicode's other name for it is z notation schema hiding.
Fullwidth reverse solidus U+FF3C. The backslash in its fullwidth form, from the block Halfwidth and Fullwidth Forms.
Mathematical falling diagonal U+27CD. A longer diagonal that Unicode cross-refers to set minus, added in version 6.1 (2012). \diagdown in LaTeX, with the amssymb package.
Reverse solidus U+005C. The backslash of the keyboard. Unicode cross-refers it to set minus and keeps the two apart. \ in HTML, \backslash in LaTeX.
Reverse solidus operator U+29F5. A backslash made to be a math operator, in Unicode since version 3.2 (2002).
Small reverse solidus U+FE68. The backslash in a small form, from the block Small Form Variants.

How this list was compiled: Names, and the code points they belong to, are checked against UnicodeData.txt, version 18.0.0 (https://www.unicode.org/Public/18.0.0/ucd/UnicodeData.txt), and printed in sentence case. Notes that begin Unicode's note, and the other names Unicode gives a character, quote NamesList.txt of the same version (https://www.unicode.org/Public/18.0.0/ucd/NamesList.txt), as do the look-alikes Unicode cross-refers; the version a character was added in is from DerivedAge.txt (https://www.unicode.org/Public/18.0.0/ucd/DerivedAge.txt) and the years are from https://www.unicode.org/history/publicationdates.html. Block names are from Blocks.txt of the same version. Alt codes are from the code page 437 table (https://www.unicode.org/Public/MAPPINGS/VENDORS/MICSFT/PC/CP437.TXT) and the code page 1252 table (https://www.unicode.org/Public/MAPPINGS/VENDORS/MICSFT/WINDOWS/CP1252.TXT); a character in neither has no Alt code here. That some apps, rich text editors in particular, read an Alt code from 256 to 65,535 as a Unicode code point: https://en.wikipedia.org/wiki/Alt_code. Option keys are those of the U.S. keyboard layout as CLDR records it (https://github.com/unicode-org/cldr/blob/release-42/keyboards/osx/en-t-k0-osx.xml). HTML entity names are from https://html.spec.whatwg.org/entities.json. LaTeX macros are listed only when LaTeX's own fontdef.dtx (https://github.com/latex3/latex2e/tree/develop/base) or the amssymb source (https://ctan.org/pkg/amsfonts) defines them, matched to a code point through unicode-math-table.tex (https://github.com/latex3/unicode-math). What the set difference is, how it is written (the sign of ISO 31-11, the minus sign and why it can be misread), the examples, the complement and its notations, and how LaTeX sets the sign: https://en.wikipedia.org/wiki/Complement_(set_theory). Union, intersection and symmetric difference: https://en.wikipedia.org/wiki/Glossary_of_mathematical_symbols. Which bracket includes an endpoint and which leaves it out: https://en.wikipedia.org/wiki/Interval_(mathematics). That set theory is a topic of discrete mathematics: https://en.wikipedia.org/wiki/Discrete_mathematics. All read on 2026-10-09 and restated in this site's own words. The Start here group, the made rows and the order are this site's own choice. Licence: own work (facts from the Unicode Character Database, Unicode License v3, and from Wikipedia, CC BY-SA 4.0, restated in this site's own words; aliases and notes marked as Unicode's are quoted from NamesList.txt, Copyright © 1991-2026 Unicode, Inc., https://www.unicode.org/license.txt)