title: Excel: counting data for different days of different weeks ( variable rows count )
body: <p>I have a report with data for different dates. 
  As I have a daily report, I need to sum the quantity of data ( Paid, Done ) column for an every specific week. 
  With the help of Weeknum I detected the number of a week, and now I need to calculate the sum of this data for a specific week. 
  How can I accomplish that? 
  I tried SUMIF - it didn't help.
  <a href="https://i.stack.imgur.com/xct0C.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/xct0C.png" alt="enter image description here"></a></p>