How to dynamically calculate the total sum ？

[lj4353]

I have created two entities, otherIncome and bonus, establishing a one-to-many relationship between them. My goal is to dynamically calculate the total sum of the amount field in the bonus entity and instantly display it in the number field of the otherIncome entity. Currently, I have to make modifications to the otherIncome entity and reload to update the number field. However, I want to see the update simultaneously as I modify the amount field in the bonus entity. What steps should I take to achieve this real-time synchronization?