On my TI-89 Titanium, I created a simple function (not program) through the built-in program editor tool, and all of the output methods that I've tried, Output and Disp display it on a seperate screen from the math home screen that lists all the calculations you've done. Return doesn't work for this either, Return doesn't show the number and just says done. It's pretty inconvenient and prevents me from using ans. If anyone knows how to do this, I'd greatly appreciate that information shared with me, thanks!
TI-89 Titanium outputting a number from function on the actual home screen