Probably the wisest way to use one cell to do this would be to put the
following in the cell:

=127

When you get a $50 receipt, change it to:

=127+50

When you get another receipt, say 34.95:

=127+50+34.95

The reason to do it this way is so that if you happen to make a mistake
when entering the value, you don't lose your previous data.

Scott

Brecken wrote:
How do I create a function or formula in acell to perform this operation?
(i.e if I have the number 127 in a cell and want to to enter 50 into the same
cell so that I get a sum of 177 in the same cell, how do I do this, rather
than adding the 2 numbers in my head, and manually entering 177?) I am doing
this for purposes of a budget and entering receipts. If the amount I've
spent on groceries is $127 up to the present time, and I want to add an
additional grocery receipt of $50, I want to be able to have the cell add the
new entry, rather than adding the 50 in my head and enter $177. Thanks!