It's a calculator based on what you press to your calculator. In CalcStroke the operator precedence applies. (The language is based on my experience of golfing my calculator strokes.)
In CalcStroke there is an implicit
=, so you don't need a
= at the end in order to calculate your answer.
Or, since CalcStroke also supports the n variable:
Digital root formula
5 + 5 = 10