I often use dc(1) so my first instinct was to type "1 2 3 +" into the input without intermediate linebreaks. I was delighted to see that this was correctly understood to mean what I wanted to express instead of it doing something silly like taking just the first int of my string or trying to parse the string as a whole straight to int.

These are the sort of things which encourage readers to read on :)

Edit: Unfortunatelly, when I try to scroll and read the rest, the input field steals focus rendering me unable to continue. Firefox on Android.