See:
Calculated fields
at:
http://members.iinet.net.au/~allenbrowne/casu-14.html
for an explanation of how and when to do that.

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Allen Browne - Microsoft MVP. Perth, Western Australia.
Tips for Access users - http://allenbrowne.com/tips.html
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>I am designing a database in which I need to add "points earned" Saturday
>and
> Sunday of each week and some of the total on the third field. How can I
> set
> this up?
>I am designing a database in which I need to add "points earned" Saturday and
>Sunday of each week and some of the total on the third field. How can I set
>this up?
Don't store the totals in any Table. Doing so is redundant,
unnecessary, and risky: if one of the "points" fields changes, your
sum would be stored, and it would be WRONG.
Instead, store the points earned each day; and calculate the total in
a Query by typing the expression
TotPoints: [SaturdayPoints] + [SundayPoints]
in a vacant Field cell.
Or... better yet... store each day's points in a separate recrod with
the date; and use a Totals query (see the help file) to add them up.
John W. Vinson[MVP]