Function to take average of numbers using LISP

(print"Lucrarea 3")
(terpri)

(setf a 
(make-array '(3 3)
:initial-contents '((1 2 3) (4 5 6) (7 8 9))
)
)
(write a)
(terpri)

(defun afisare(i j)
(print (aref a i j)))
(afisare 1 2)
(terpri)


(setq a2 (make-array '(2 2) :displaced-to a :displaced-index-offset 5))
(write a2)
(terpri)


(setf (get 'Student'nume) 'Mihai)
(setf (get 'Student'varsta)30)
(setf (get 'Student'AnStudiu)3)
(setf (get 'Student'CNP)18403123456)
(write (symbol-plist 'Student))
(terpri)


(defun averagesum(n1 n2 n3 n4 n5 n6 n7 n8 n9)
(/(+ n1 n2 n3 n4 n5 n6 n7 n8 n9)9))
(write(averagesum 5 6 7 5  5 4 7 8 9))