The frequency adjustment knobs on aviation radios work just like volume knobs. Turning the knob left makes the numbers go down, turning it right makes them go up. If your radio is tuned, say, to 124.85 and you need to tune in 127.05, turn the knobs for frequency selection to the right, not the left, to reach the desired frequency more quickly and easily. The same goes for nav radios. It might seem like a minor thing, but over the long run it will save you a lot of knob twisting.