I have rows of data as follows:

First row is week #
Second row is the quantity ordered each week for customer # 1
Third row is the quantity ordered each week for customer # 2
Subsequent rows are allocated to other customers.

The columns are allocated week numbers and at the end of each month I have
two columns
The first column is the total for the week
The second column is the cumulative total for each month.

What I would like to do is for a macro to run when the week number is typed
in cell # A1. The week # can be 1 to 52 and may change.

Say week #1 to #4 is in January and week #5 to #7 is in February.

When week number 7 is typed into cell # A1 the information required is
required to extract the following information the
Total for week # 7 only and insert into cell E11.
Cumulative to date (week #s 1 to 7 only) and insert into cell F11.


Many thanks in advance