// Workers AI · dad joke modeWhat did the sum say to its friend? It added up to a good time.

Sum most commonly means the total of two or more numbers added together; see addition.

Sum can also refer to:

Mathematics

Sum (category theory), the generic concept of summation in mathematics
Sum, the result of summation, the addition of a sequence of numbers
3SUM, a term from computational complexity theory
Band sum, a way of connecting mathematical knots
Connected sum, a way of gluing manifolds
Digit sum, in number theory
Direct sum, a combination of algebraic objects
- Direct sum of groups
- Direct sum of modules
- Direct sum of permutations
- Direct sum of topological groups
Einstein summation, a way of contracting tensor indices
Empty sum, a sum with no terms
Indefinite sum, the inverse of a finite difference
Kronecker sum, an operation considered a kind of addition for matrices
Matrix addition, in linear algebra
Minkowski addition, a sum of two subsets of a vector space
Power sum symmetric polynomial, in commutative algebra
Prefix sum, in computing
Pushout (category theory) (also called an amalgamated sum or a cocartesian square, fibered coproduct, or fibered sum), the colimit of a diagram consisting of two morphisms f : Z → X and g : Z → Y with a common domainor pushout, leading to a fibered sum in category theory
QCD sum rules, in quantum field theory
Riemann sum, in calculus
Rule of sum, in combinatorics
Subset sum problem, in cryptography
Sum rule in differentiation, in calculus
Sum rule in integration, in calculus
Sum rule in quantum mechanics
Wedge sum, a one-point union of topological spaces
Whitney sum, of fiber bundles
Zero-sum problem in combinatorics

Sum, the first beat (pronounced like "some") in any rhythmic cycle of Hindustani classical music
"Sum", a song by Pink Floyd from The Endless River
Sum: Forty Tales from the Afterlives, a 2009 collection of short stories by David Eagleman
Sum 41, a Canadian punk band
SUM, the computer in Goat Song (novelette) story by Poul Anderson in Magazine of Fantasy and Science Fiction, (1972).

Senter for utvikling og miljø (Centre for Development and the Environment), a research institute which is part of the University of Oslo
Soccer United Marketing, the for-profit marketing arm of Major League Soccer
Society for the Establishment of Useful Manufactures, a now-defunct private state-sponsored corporation founded in 1791 to promote industrial development along the Passaic River in New Jersey in the United States
The State University of Management, a Russian university
Save Uganda Movement, a Ugandan militant opposition group
Ukrainian Youth Association (Спілка української молоді, Spilka Ukraïns'koï Molodi), a youth organization in Ukraine and countries with a Ukrainian diaspora

Sum (administrative division), an administrative division in Mongolia, China, and some areas of Russia
- Sum (Mongolia), an administrative division of Mongolia
SUM, the IATA airport code for the Sumter Airport in Sumter County, South Carolina, U.S.

Sum, an old name for the Finns in East Slavic languages, derived from the word Suomi, "Finland"
Soum (currency) (also spelled "sum"), a unit of currency used in some Turkic-speaking countries of Central Asia
SUM (interbank network), an interbank network in 42 U.S. states
SUM, the ISO 639-3 code for the Sumo language
Cen (surname) 岑, a Chinese surname sometimes romanized as Sum
Shěn (surname) 沈, a Chinese surname sometimes romanized as Sum
Cogito, ergo sum, Latin for: "I think, therefore I am"
Sum certain, a legal term