equation vs sum

equation

noun
  • An assertion that two expressions are equal, expressed by writing the two expressions separated by an equal sign; from which one is to determine a particular quantity. 

  • The act or process of equating two or more things, or the state of those things being equal (that is, identical). 

  • A small correction to observed values to remove the effects of systematic errors in an observation. 

sum

noun
  • A quantity obtained by addition or aggregation. 

  • The basic unit of money in Uzbekistan. 

  • The utmost degree. 

  • A summary; the principal points or thoughts when viewed together; the amount; the substance; compendium. 

  • A quantity of money. 

  • The basic unit of money in Kyrgyzstan. 

  • A type of administrative district used in China, Mongolia, and Russia. In Mongolia, a sum is smaller than a province. In China, it is only used in Inner Mongolia, where it is equivalent to a township. 

  • An arithmetic computation, especially one posed to a student as an exercise (not necessarily limited to addition). 

  • A central idea or point; gist. 

verb
  • To add together. 

  • To give a summary of. 

How often have the words equation and sum occurred in a corpus of books? (source: Google Ngram Viewer )