Definition
To have a plan, intention, or idea already formed in one's mind.
心中有數
I don't have anything specific in mind, but I'm happy to hear your suggestions.
我沒有具體的想法，但我很樂意聽聽你的建議。
Before we start this project, we need to know what you have in mind.
在我們開始這個項目之前，我們需要知道你心裡的想法。
She seems to have something in mind, but she is not willing to share.
她似乎心裡有想法，但她不願意分享。