How do you calculate gas mileage when traveling?

To determine how far a car travels on its fuel, it's necessary to know how much gas it can hold. The car also needs a working trip odometer. By using division and other arithmetic, it's simple to calculate a car's approximate gas mileage in miles per gallon.

First, get to a gas station and completely refill the car from about half a tank of gas. Make a note of the gallon measurement, then reset the car's odometer. Then, drive until the car has half a tank again and check the odometer. Divide the number of miles driven by the amount of gas used to fill the tank to get the miles per gallon measurement.