easy as pie vs elementary

easy as pie

adj

  • Very easy. 

elementary

adj

  • Relating to the basic, essential or fundamental part of something. 

  • Relating to an elementary school. 

  • Relating to a subatomic particle. 

noun

  • A supernatural being which is associated with the elements. 

  • An elementary school 

How often have the words easy as pie and elementary occurred in a corpus of books? (source: Google Ngram Viewer )