What you can reset is the car’s trip computer, which is similar to the odometer. This counts how many miles you’ve driven since you last reset the trip computer, and in most cars you can track two or more different trips at once. This means you might have 30,000 miles on the odometer, but only 100 miles on “Trip A” or “Trip B”.
On the dashboard near your Mazda 3’s odometer, you’ll see a small, long button that looks like a stick. If you press and release this button, you can switch between the two trips. If you press and hold this button, you’ll reset the trip that’s showing back to zero. This works in most cars, too!