Credit and Debit formating

I have workbook that has one tab that pending credits and charges are
entered by associates who are not Excel suavy. That information is linked to
a cell for reconcilation. The purpose is to figure a inventory.

How it works is
actual count plus pending items to come up with a new inventory balance. The
problem is I need to add back into the inventory the credits and take out
the charges. Do to the fact that these credit debits are entered in the same
place. What I am trying to do is convert the credit to charges and subtract
the debit (opposite of value). Is there a formula that can do this?

Can you post the file or an example of how the debits/credits are displayed?