test:
``` clojure
;; automatic_type_casting.clj
42
(type 42)
(type 42.5)
(+ 42 42.5)
(type (+ 42 42.5))
42.7M
(type 42.7M)
(+ 42.5 42.7M)
(type (+ 42.5 42.7M))
(type (+ 42 42.0))
(type 994824757458783748579437258798745.278375725925479247582945754M)
(type (+...
```