Addition and Contrast

Contrast may refer to:
Science
Contrast (vision), the contradiction in form, colour and light between parts of an image

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  Contrast (statistics), a combination of averages whose coefficients add up to zero, or the difference between two means
  
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  Behavioral contrast, a phenomenon studied in psychology (behavior analysis)
  
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  Contrast agent, used to distinguish structures or fluids within a body, often shortened to just "contrast"
  

Technology

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  Contrast ratio, a measure of a display system
  
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  Display contrast, of electronic visual displays
  

Language

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  Contrast (linguistics), expressing distinctions between words
  
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  Contrast (literary), describing the difference(s) between two or more entities