; recap from last time (about lists)

(define list1 '(a b))
(define list2 '(1 2))

; what do the following commands return

(append list1 list2)
; can take in any number of lists and will stick them together

(cons list1 list2)
; cons expects two arguments, an item of any kinds and a list and it makes 
; that item the new first element of the list

(list list1 list2)
; list can take any number of arguments and make a new list to put them in


; PROCEDURES (functions)
; when writing a procedure, we use the LAMBDA command to bind
; values to variables
; syntax:   (lambda VARIABLE-LIST EXPRESSION)

(lambda (a b) (+ a b))  ;example

(define add 
  (lambda (a b) 
    (+ a b)))

; Given: A, B positive integers

; Result: MULTIPLE-OF? a boolean value (#t or #f)

; Precondition: none

; Result: MULTIPLE-OF? is #t if and only if A is a multiple of B

(define multiple-of?
  (lambda (a b)
    (= 0 (remainder a b))))