You have to create an entity with two attributes for the values and one for the sum. Put that entity in a dataview on your page and onchange recalculate and refresh the entity.
There are two ways of doing this. The first is using the attribute’s option to calculate the value using a microflow. The second only uses nanoflow, which gives you the best ser experience, since the result will update instantanious
You need to take a couple of steps:
MF1/NF1: (link/bind to the Data view) – use a nanoflow to process this in your browser (microflows execute on the server).
MF2 / NF2: (Link to the button). I recommend you use a nano-flow to offload the calculation to your browser and not the server.
The calculation happens in the Change Calc Action. See below:
Hope this helps :)