title: SUMPRODUCT Formula using Date and Values - Won't work when I move to another Sheets
body: <p>I'm having issues with a formula, it works fine on the sheet that has the data as I'm using it to calculate figures based on a sales by month basis</p>
  
  <pre><code>=SUMPRODUCT((MONTH(G:G)=3)*(YEAR(G:G)=2017)*(M:M))
  </code></pre>
  
  <p>there is too much info on the sheet i'm using so want to move this formula to another sheet in the same work book, but when I add the usual reference sheet formula it doesn't work.</p>
  
  <pre><code>=SUMPRODUCT((MONTH('Stock'!G:G)=3)*(YEAR('Stock'!G:G)=2017)*('Stock'!M:M))
  </code></pre>
  
  <p>Can Anyone Help - I'm Intermediate in Excel and bundled through just to get this far</p>