Diamond, we often omit pronouns if whom the sentence refers to is otherwise clear. In your sentence, you include "I" to indicate the person is asking you the question. Because this is clear, the inclusion of "me" is truly optional. Some would say it is redundant, but I think that most English speakers would tend to include the "me" in this sentence. Without "me" the language sounds a little "poetic", with "me" the language sounds more conversational. I suspect a trained writer would leave it out. I suspect those of us who are not writers would leave it in.

Both ways are correct. The difference is very simple. "Me" adds more information. Some verbs--gave, sent, asked, told, bought, found--can have two objects: My co-workers bought me a new briefcase because my old one was so ugly! There are two objects--"me" and "a new briefcase." Or, change the order: My co-workers bought a new briefcase for me because my old one was so ugly! Most verbs--washed, experienced, cut, spent--only use one object: Since I lost the bet, I washed his car. We can't add a second object: Since I lost the bet, I washed Jerry his car. (Nooooo! It's wrong.) One object? Two objects? No objects? How do we know? Practice. I made a video with some tips, if you need more practice: http://www.youtube.com/watch?v=z0oqJpTu7Pw Enjoy! Dan

both reported statements are correct. You may eliminate the use of "me" if you want to focus to the fact that he have asked about something or the person he have asked to is unimportant. But many language teacher would prefer you add "me" there because it's more structurally acceptable.

if you want to add me ,this sentence should be :he asks me that how many friends do i have. if u dont add me ,this sentence---he asks how many friens do i have, it is right.

I think you can add "me"