approximation vs estimated price/cost/value

approximation

noun
  • The act of bringing together the edges of tissue to be sutured. 

  • An imprecise solution or result that is adequate for a defined purpose. 

  • The act, process or result of approximating. 

estimated price/cost/value

How often have the words approximation and estimated price/cost/value occurred in a corpus of books? (source: Google Ngram Viewer )