The number that keeps jumping behind the buying and selling price in the upper right corner of the futures K-line is the number of buy or sell pending orders at that price, and the unit is "hand".

The following figure is a picture of SR 1509, in which 26 indicates that 26 lots were sold at the price of 5589, and 200 indicates that 200 lots were sold at the price of 5588. Due to the change of investors' views on the market, the selling orders and buying orders will change constantly during the trading hours. The more active the variety, the more frequent the change.