I’m using MediaWiki with the “Semantic MediaWiki” extension. I would like to be able to use a command to increase a tally by whatever amount I input, such as to list a total price for items entered. (I imagine it to look something like: {{#AddToTally:MyVariable|123}}.)

I tried the extension “Semantic Result Formats”, thinking that its “|format=sum” option would do the trick, but I discovered that multiple identical values assigned to a property get condensed into one. (For example, three car parts valued at $500, $500, and $1000, would end up being treated as $1500 total, rather than $2000 as I had hoped.)

What few alternative extensions came up in my search attempts were things like arrays, and frankly I find all the math and brackets and special terms impossible to digest. If I knew the technical jargon for what it is that I seek, my searches might prove more fruitful.

The “Counter” extension seemed like it might be what I needed, but my wiki wouldn’t work with it installed, and the extension’s page says it’s no longer maintained.

Suggestions?