Assuming that the settlement price of the previous trading day was 625.40, the nearest integer execution price should be 625.00;

Based on this exercise price, five real options (in money 624,623,622,621620) and five hypothetical options (outside money 626,627,628,629,630) are set respectively.

So you can see that if 625.40 is the settlement price of the last trading day, then the boundary of the hypothetical option must be 625 (that is, 625.40 is rounded off), and the closest exercise price must be 620 (at this price) to ensure that 625 can be exercised.

Hehe, young people study well.