#### 4.2.3 Sequencing

— library syntax: begin <expression1> <expression2> ...

> The <expression>s are evaluated sequentially from left to right, and the value(s) of the last <expression> is(are) returned. This expression type is used to sequence side effects such as input and output.

>     (define x 0)

>          (begin (set! x 5)
>                 (+ x 1))                        ==>  6

>          (begin (display "4 plus 1 equals ")
>                 (display (+ 4 1)))              ==>  unspecified
>                    and prints  4 plus 1 equals 5