Freezer thermometer: reads almost 20 degrees between the freezer 0 and the refrig 0. ...don't know if I am supposed to use the + side or - side to read...is it 20 degrees ABOVE 0 or is it about 14 degrees BELOW freezing? I do no know which way to set the temp dial on new refrigerator! Unable to find another easier to read brand and will appreciate your help! Freeda Carter