Simple Excel Formula

OK all you Excel gurus out there - I have a problem but I know it's going to be a very simple one for all of you.

I have an Excel file that consists of 12 worksheets, one for each month. Each month has a total at the end of the page. In the last month of December I would like to add all the totals from each month so that they appear on the December page - any help with the formula would be very much appreciated.

1) Go to the December sheet and click on the cell that will contain the total.

2) Type = sign

3) Click on the Jan tab and click on cell that contains Jan total

4) Type the + sign

5) Click on the FEB tab and click on cell that contains FEB total

6) repeat step 4 and 5. In step five the months will change. Mar, Apr etc..