xfce4-calculator-plugin 0.6.0 371.48-375= -3.519999999999982 10-9.53 0.4700000000000006 etc. Problems with calculation accuracy.
This is how calculator-plugin formats the operation result: g_strdup_printf("%.16g", r); That mask could be simplified to "%g" so the outputs are "-3.52" and "0.47" as expected. I reviewed the source code history and there has been a fixed decimal length since the first commit. Well, it's pretty easy to change that mask, I'm just not sure if that would result in undesired formatting.
This isn't really a bug. Maybe the formatting could be configurable instead. If it's really that important to you please file a feature request describing your use case. Thanks!