What took the longest to click for me is that there is no distinction between a variable and an array in mathematics- if you write x_i = y_i you are equating each element of two potentially infinite sets.  There are implicit looping operations everywhere.  Also in the equation x=2y x and y are not variables in the programming sense of the word but rather every pair of x and y that are a solution is a member of the solution set.  So it&#x27;s a very different approach.