depress vs subtract

depress

verb
  • To reduce (an equation) in a lower degree. 

  • To cause a depression or a decrease in parts of the economy. 

  • To make depressed, sad or bored. 

  • To press down. 

  • To bring down or humble; to abase (pride, etc.). 

subtract

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

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