how to get the average of score?

[beauty]

i have some trouble on my database document, on the first column filled by "mahasiswa name", the second colmn filled by "nama mata kuliah", the third column filled by "Nilai" in this table i select number as the data type, the fourth column filled by "indeks prestasi" or usual called by "ip",i want ask about how to combine all of "ip" from all of "mata kuliah" or you may know as subject, after i accumulate they ip so i'll get the average of ip for one person.. just help me to solve it,

[orange]

I'm not sure what you are asking. Can you show your table layouts, and any query you have tried? Also, if you are getting an error message, please include it.