When the tank is full the resistance of the sending unit's pot is the lowest (typically 10 ohms, float up) so that the maximum current can flow through the gauge and the needle can swing fully to the right. When it's empty the resistance is the highest (typically 73 ohms, float down) so that the minimum current can flow and the needle stays on EMPTY.
If you are reading your meter on the 1K ohm scale you're about right (0.01 X 1000 = 10 and 0.08 X 1000 = 80 ohms).
