How does Mr Wormwood turn back the odometer in a car?

In the book "Matilda" by Roald Dahl, Mr. Wormwood, Matilda's father, turns back the odometer in a car by using a drill. He removes the speedometer and then manipulates the device to roll back the numbers, effectively deceiving potential buyers about the car's true mileage. This dishonest practice reflects his unscrupulous nature and lack of integrity.