good 字的問題

This medicine is good for you
這藥對你好的/有幫助的

I am good at math.
我精於數學

I am good with you.
有你,我覺得好好.
Weather there was very good with blue sky and bright sunlight.
那兒的天氣好好,有藍天艷陽

good for good at good morning good night