- Soulver, according to the screenshots (and the goal of this project seems to match Soulver's behavior),
- the calculator on my phone,
- KRunner, the launcher in KDE, and KCalc, its calculator
- gcalc, the Gnome calculator
- qalc, that shows "25 * (110 * percent) = 27,5".
- The TI-106 solar calculator that I happen to have [1].
Thinking about it, we are probably talking about some kind of "+ %" operator, where x + y % = x + x × y / 100.
Interestingly, 10% = 0 for the TI-106 (but 25*10% = 2.5). % alone does not seem to mean anything for it.
This little calculator will probably outlive me.
[1] http://www.datamath.org/BASIC/LCD_Modern/TI-106_2.htm