I have a spreadsheet with data that shows transactions for a number of areas
with a column showing which week the transaction belongs to eg (I have put
row and column headings on for clarity later):

Sheet1

A B C D
1 Area Week No Value Description
2 1 10 52.25 bread
3 1 10 14.12 milk
4 1 11 15.25 bread
5 2 12 28.24 butter

etc

I then want to populate another sheet with these transactions summarised by
area

Sheet2

A B C D
1 Area Week 10 Week 11 Week 12
2 1 66.37 15.25 0
3 2 0 0 28.24

I can't use a pivot table because I have a number of different worksheets
for different suppliers that are in a different format that also need to be
shown on the summary sheet.

I'm thinking that this could be done by using a sumif formula on sheet 2
that refers to both the area and week number. Is this possible please?