multiplication vs piling up

multiplication

noun
  • The process of computing the sum of a number with itself a specified number of times, or any other analogous binary operation that combines other mathematical objects. 

  • The process of multiplying or increasing in number; increase. 

  • A calculation involving multiplication. 

piling up

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