Sum-up all quantity of products in Total sheet

[Naghman]

Hi. I want to get total of different products in Total-sheet ?
I have a file with 11 worksheets. A:A contains product numbers (they are in different orders) & in E:E are quantity. My question is how to find matched product number & add its quantity in TOTAL-sheet?
I have tried =SUMIF($A:$A;'Omr. 1'!$A:$A;'Omr. 1'!$E:$E)+=SUMIF($A:$A;'Omr. 2'!$A:$A;'Omr. 2'!$E:$E)
But it does not work.
I shall be very thankful if some one helps me out.
regards
/naghman