To sum up the Datas of a particulars in a column

I have a sheet pertaining to datas plant wise.I have 3 plants datas having month wise figures e.g.Apr'10~Aug'10.Each plant have a fig.in a specific month with their different heads.Now,I want the sum of all my 3 plants into a summary column.I am applying the sum of a plant by adding formula one by one.It is very cumbersome formula.Is there any formula to solve the problem by Excel?

Please refer the attached sheet.

Regards

Pradeep Kumar Gupta

Thank you very much sir.

Regards

Pradeep