Note - study information - 
https://cs.indstate.edu/wiki/index.php/R_Programming_-_Getting_Started#The_Basics_Quizzes
https://cs.indstate.edu/wiki/index.php/R_Programming_-_Getting_Started#Cheat_Sheets
https://cran.r-project.org/doc/manuals/r-release/R-lang.html#Reserved-words
https://cran.r-project.org/doc/manuals/r-release/R-lang.html#Special-operators
https://cs.indstate.edu/wiki/index.php/R_Programming_-_Getting_Started#R_Functions