For example, double click on a text object on any HMI screen. Go to the "Value" tab and check "Enable Value Animation". In the entry field you can select a PLC variable and add scaling factors. It might be something like "PLC_Target.PLC_Variable * 0.01". When you do it that way, the specific instance of the variable on that screen is scaled.
You can also do the scaling in the setup of the HMI variable. When you do it that way every instance of the HMI variable is scaled.