Accumulate

Please help me figure this out:

Say I have a column of numbers that I need to sum every day.

No problem - this is easy.

Next day I need to erase all the previous' day's numbers.
Then I put in new numbers
Then I total them

Next day I erase, put in new and total those etc. day after day.

Here comes the perplexing part:
The total for each day needs to be added to the total of the next day, that total then needs to be added to the total of the next day etc.

In other words: How can I keep adding (accumulating) totals despite the fact that I have to erase each days numbers but NOT each day's totals?

This prosess seem to involve some manual labour anyhow, so can you not simply include a cell in your sum where you put in yesterdays sum by copying the value of yesterdays sum before you erase yesterdays data ?