While obviously it's a fundamental thing to teach/cover the various data types (or at least how '1', 1, and 1.0 are different since they'll be encountering this

While obviously it's a fundamental thing to teach/cover the various data types (or at least how '1', 1, and 1.0 are different since they'll be encountering this over and over if they continue programming), on a practical level, frequent casting can be sidestepped by using string formatting when printing numeric output. In all my production code (my string printing is not performance critical) I pretty much always use string substitution when printing as a matter of style/convenience. It's much easier to add/replace substitutions, and I often need formatting anyway. If students get used to printing w/ string substitution, they can then simply use %d or %f to control how they want their numbers to display, which is probably the right way of thinking about rendering text output.