##Problem 1:

###test cases:

(let (fred 12) (+ fred 1))

variable "fred" value does get cleared returns 13

fred

returns fred

(let (a 1))

just assigns a with value 1 retains its value until used in "(let (x 1)(+ x 1))"-like format

a

returns 1

(+ a 3)

returns 4

(- a 3)

returns -2

(* a 3)

returns 3

(/ a 3)

returns 0.333333

(/ a 0)

returns error message

(if #f 10 13)

returns 13

(if #t 21 13)

returns 21

###extra notes:

+, -, /, * all supported variable clearing done as specified

##Problem 2:

###test case:

(car '(1 2 3))

###extra notes:

we just did what professor Cannata did in class