PART 
  1.  Create an implementation of natural numbers
  2. Implement plus
  3. Implement equal
  4. Implement less than
  5. Implement greater than
  6. Implement minus
  7. Implement multiplication
  8. Implement mod/remainder
  9. Implement factorial
  10. Extra credit: implement number so that number (X, N)  is true if X  is a numeral corresponding to the decimal integer N. For example, number (s(z),1) is true and number (s(s(s(z))),2) is false.
  11. Extra credit: implement e_number, so that e_number(X, Y)  is true if Y is a phrase in English for positive natural numbers between zero and 100, representing X.  For example:
Submit (2) working .pl files that demonstrate  the cases above with code comments and test cases.
                                                                                        Last Revised: January 21, 2018