fill in vs subtract

fill in

verb
  • To fill; to replace material that is absent or has been removed. 

  • To substitute for somebody or something. 

  • To complete a form or questionnaire with requested information. 

  • To beat up; to physically assault. 

  • To inform somebody, especially to supply someone missing or missed information. 

subtract

verb
  • To remove or reduce; especially to reduce a quantity or number 

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