Need consolidated information

I'm not sure that there's an easy way to do this, might be relegated to cut and paste, but I thought it was worth asking...

I have a spreadsheet from our booster club, in which they have kept each month of check register in an excel table in each of 12 different tabs (i.e. Jan15, Feb15, etc.).  Each table is obviously variable in length, and contains pretty much what you'd expect (check#, date, description, category, withdrawal, deposit, balance).  They would like to summarize the categories across all 12 months (sum the deposit-withdrawal for each category (just so withdrawals are negative).

For example, Jan15 might look like

Check        Date                        Desc                                                Category                   Withdraw                Deposit               Balance
114           01-Jan-15    French fries for concessions                Concessions                    75.00                                               2,500.00
115           05-Jan-15            Cleaning Supplies                           Field House                     10.00                                               2,490.00
                  06-Jan-15        Pizza Fundraiser                                 Fundraiser                                                         200                2,690.00

What we are trying to get is a tab that sums ALL 'concessions' category line items, all 'field house' category, etc.