;; A List of Number is either
;; - empty
;; - (cons Number List-of-Number)

;; ToDo: Write the Template for list-of-number

;; Design a function 'count-occurences' to count the number of times 9 appears in the list


;; Design a function 'add-on' which adds 10 to the value of each number in the list


;; Design a function 'replace' which replaces all the number 9s with the number 8s in the list


;; Design a function 'find-max' which returns the largest number in the list
;; use the function max to compare two numbers
;; max: number number -> larger of two number


;; Redesign 'find-max', this time dont use the function max to compare
;; Hint: find-max1: list-of-numbers -> number
;;       find-max1-help: list-of-numbers number -> number