Illustrated Commentary on Nine Chapters, Vol. 1

The answer is obtained in the middle position. For the division formula, place the dividend in the middle position and the divisor in the lower position. Place the quotient in the upper position. This is what the Sunzi Suanjing Master Sun's Mathematical Manual refers to when it says, "Multiplication results in the center; division results in the upper." As this is the beginning of the chapter, I have written it out in detail to preserve the ancient method; it will not be mentioned again hereafter, so one may understand it from this.

Now we have a field one li Chinese unit of distance, approx. 500 meters wide and one li long. The question is, how much is the area of the field?
The answer says: 3 qing unit of land area, 100 mu and 75 mu unit of land area.

Another field is 2 li wide and 3 li long. The question is, how much is the area of the field?
The answer says: 22 qing and 50 mu.

Fields of Land Measured by Li

The method says: Multiply the numbers for width and length in li to get the area in square li. Multiply by 375.