You can't without using VBA. A cell contains either a formula or value but
not both.

Perhaps you need separate "summation" categories so individual items
classified as "groceries" (and other groupings) are totalled in a "groceries"
total.

"Roberta" wrote:

I am keeping a spreadsheet of my monthly spending. How do I add to a number
that is already in a cell? For example, in the category "groceries" I have a
total of $182and I want to add 47.00 to it. I tried just writing + 47 in the
fx line and I tried sum: but it didnt' work. I know this is something simple
but I'm stuck. Thanks.