1.
Let's arrange the similar units we have learned in descending order: kilometer, meter, decimeter, centimeter and millimeter.
2.
Use the five fingers of the left hand to represent the arranged units in turn. That is, the thumb is kilometers, the index finger is meters, and the little finger is millimeters.
3.
Then consider the propulsion speed between every two adjacent fingers and make a "clever" note. The opening between the index finger and thumb is large, and the forward speed is
1000
The mouth between the other fingers is small, and the ratio between every two adjacent fingers is
10
You can use your left hand as a mirror to do this kind of problem. For example, what is the permeability of component meters per kilometer? By observing the fingers, we can find that the thumb to the middle finger are not two adjacent fingers, and the speed of progress should be "
1000
×
10
"; For another example, when the meter is converted into millimeters, it should be from the index finger to the little finger, and the speed of progress is "
10
×
10
×
10
"。