title: Get week number by year and month
body: <p>How to get Firstdayofweek and Lastdayofweek based on given year and month and week number (week number of that month)?</p>
  
  <p>I am able to get FirstdayofWeek, but when I try for February (2018, 2, 1) with week 2 the output date is incorrect.</p>
  
  <pre><code>Dim firstDayOfWeek As date
  firstDayOfWeek = DateSerial(2018, 2, 1) 'february 2018
  firstDayOfWeek = DateAdd("ww", 1, firstDayOfWeek)  'week 2
  </code></pre>
  
  <p>Output:</p>
  
  <blockquote>
    <p>2/8/2018 12:00:00 AM</p>
  </blockquote>
  
  <p>Expected Output: </p>
  
  <blockquote>
    <p>firstdayofweek: 2/5/2018 <br/>
    lastdayofweek: 2/9/2018</p>
  </blockquote>