Resolution Digital Voltmeter
3 1/2 digits means the most significant digit can only show a 1 or nothing at all, so the most segments that can be displayed are 1888.

A 40V range would not be able to use the most significant digit, so you only have 3 digits that can be used to display the value, so you can only display up to 40.0

So your least significant digit there represents 100mV (0.1V), which is your resolution.