The position index of a futures variety refers to the "average position price" of the position contract of that variety in all months. The number of futures of a certain variety refers to the "average transaction price" of the contracts of that variety in each month. The average price of positions is the weighted average price of positions at each price. The average transaction price is the weighted average price of each price according to the volume. (The average position is equal to each price multiplied by the position of that price, and then divided by the total position. Average transaction price, similar)