1-1

1-1 is a mathematical expression that evaluates to:

• 0 (number) (in ordinary arithmetic)

The term 1-1 may refer to:

• New Year's Day, a public holiday in many countries, held annually on the first of January
• Schweizer SGP 1-1, an American glider design
• World 1-1, the first level of Nintendo's Super Mario Bros.

See also

• 1:1 (disambiguation)
• 1+1 (disambiguation)
• One-to-one (disambiguation)