;  definition of add1
(defun add1 (x) (+ x 1))

   ;  definition of sub1
(defun sub1 (x) (- x 1))

   ;  definition of double
(defun double (x) (* x x))

   ;  DEFINITION OF LESSP
(defun lessp (x y)
      (! (>= x y)))

   ;DEFINITION OF GRTP
(defun grtp (x y)
      (! (<= x y)))

   ; DEFINITION OF MINUS
(defun minus (x)
      (* x -1))

   ; DEFINITION OF ABS (ABSOLUTE VALUE)
(defun abs (x)
      (if (lessp x 0) (print (minus x)) (print x)))

   ;DEFINITION OF COMPARE
(defun compare (x y)
      (cond ((equal x y)     'numbers-are-the-same)
            ((lessp x y) 'first-is-smaller)
            ((grtp x y)  'first-is-bigger)))

   ; DEFINITION OF COMPUTE
(defun compute (op x y)
      (cond ((equal op 'add)      (+ x y))
            ((equal op 'subtract) (- x y))
            ((equal op 'multiply) (* x y))
            ((equal op 'divide)   (/ x y))
            (t '(I do not know how to do that))))











(* x y))