1+1

1+1 is a mathematical expression that evaluates to:

• 2 (number) (in ordinary arithmetic)
• 1 (number) (in Boolean algebra with a notation where '+' denotes a logical disjunction, see logical disjunction#Definition)
• 0 (number) (in Boolean algebra with a notation where '+' denotes 'exclusive or' operation, see Boolean algebra#Values, or in a quotient ring of numbers modulo 2)

The terms 1+1, One Plus One, or One and One may refer to:

1+1

• 1 + 1 + 1 + 1 + ⋯, a mathematical divergent series
• 1+1 (TV channel), a Ukrainian TV channel
• 1+1 (album), a 1972 album by Grin
• 1 + 1 (album), a 1997 duet album by Herbie Hancock and Wayne Shorter
• "1+1" (song), by Beyoncé Knowles

One Plus One

• OnePlus One, an Android smartphone
• One Plus One, original title of Sympathy for the Devil (film)
• One Plus One, 2002 graphic novel published by Oni Press
• OnePlusOne, (Marriage and Partnership Research) founded in 1970 by Dr Jack Dominian

One and One

• One and One (musical)
• One and One (song)
• A type of free throw in basketball
• Dublin slang for a serving of fish and chips

Other

• One & One (musical comedy), an American 1970s off-Broadway musical comedy
• 1&1 Internet, a web hosting company

See also

• One and One Is One (disambiguation)
• One Plus One Is One (2004 album), album by Badly Drawn Boy