Please help!!!! Extremely difficult formula to create?

First, 8 digits are numbers. The last 3 are the checksum.

I am NOT asking for just how to get the last three digits by selecting the last 3 digits.
I am asking HOW the three last digits are computed and asking for a formula for how these numbers are computed.

number. Checksum
62831049 448
62831050 289
62831051 103
62831052 918
62831053 732
62831054 557
62831055 371
62831056 196
62831057 011
62831058 825
62831059 640
62831040 187
62831041 901
62831042 716
62831043 531
62831044 355
62831045 170
62831046 094
62831047 819

What will be the three-digit checksum for
63960567

???

The correct formula should provide the last 3 digits of the above sample.

actually, this is a question asked by my friend I have racked my brain for 4 hours but still couldn't find a proper formula Please HeLP

Administrative Note:

We would very much like to help you with your query, however the thread title does not really convey what your request is about. Tell us what you are trying to do, not how you think it should be done.

Please take a moment to amend your thread title. Make sure that the title properly explains your request. Your title should be explicit and not be generic (this includes function names used without an indication of what you are trying to achieve).

Please see Forum Rule #1 about proper thread titles and adjust accordingly. To edit the thread title, open the original post to edit and then click on Go Advanced (bottom right) to access the area where you can edit your title.

(Note: this change is not optional. No help to be offered until this moderation request has been fulfilled.)

Your title should state what you are trying to do. Not going to do it for you, sorry - there's enough in the text of your opening post to give you what you need. You need to make an effort.

Try again, please.

EDIT: The change in your last post is OK, but the change needs to happen to the opening post of the thread. Edit that and make the change there, please.

No, it's NOT OK!!! It doesn't tell us what you want to do.

Change it to something that tells us something about the checksum you wish to generate.

I am NOT going to do it for you - sorry. Get it sorted out and then I will clean up the thread.

You have been a member here long enough to know the rules and not to expect to have your hand held in this way.