favourable vs plus sign

favourable

noun
  • A favourable person 

adj
  • Pleasing, encouraging or approving. 

  • Useful or helpful. 

  • Auspicious or lucky. 

  • Convenient or at a suitable time; opportune. 

plus sign

noun
  • The symbol + used to denote the operation of addition, to indicate that a number is positive, and so on. 

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