Hi, George
You can change the values via the arrow keys on the keyboard. It’s also possible to click on the label and drag to change the values, but I don’t particularly think it’s very accurate. Maybe one of these two ways can help you.
You might want to take a look at this topic that also deals with changing values in the properties panel: [Technical limitation] Using scroll to change properties without scrooling the panel - #9 by Luni
Edit.: I moved your topic to the Feature Request category.