title: SumProduct #VALUE error array formula - trying to use "--"
body: <p>So .. i tried to use</p>
  
  <pre><code>={SUMPRODUKT(($F$3:$F$84=$N4)*($G$2:$L$2=O$3)*$G$3:$L$84)/2}
  </code></pre>
  
  <p>this cant handle if one of the values in the last range G3:L84 happens to be a an letter</p>
  
  <p>so i have done some reading .. and if it was a matrix i should be able to use"--" double negating.. 
  this is how ever not working</p>
  
  <pre><code>={SUMPRODUKT(--($F$3:$F$84=$N4)*--($G$2:$L$2=O$3)*--($G$3:$L$84))/2}
  </code></pre>
  
  <p>It still works unless i have values not existing</p>