title: SUMIF with FIND as criteria
body: <p>I'm trying to summarize data from several Google spreadsheet' sheets in a single one but I have some issues with SUMIF and FIND.
  To Sum data from another sheet I have to use this (at least that's the only solution I've found)</p>
  
  <pre><code>=SUM(INDIRECT(""&amp;A6&amp;""&amp;"!E2:E"))
  </code></pre>
  
  <p>Where I have the name of my sheet on A6.This makes everything easy because I have a column (A) with all the names of the sheets. I haven't found something like Sheets[1] in Google Docs.</p>
  
  <p>My next step was to Sum Times from a specific column but remove a specific values, which in this case is 1 that get transformed internally 24:00:00 since it's a time column:</p>
  
  <pre><code>=SUM(INDIRECT(""&amp;A6&amp;""&amp;"!D2:D")) - SUMIF(INDIRECT(""&amp;A6&amp;""&amp;"!D2:D");"24:00:00")
  </code></pre>
  
  <p>Here I tried to do everything with a single SUMIF but I have no idea how. NOT("24:00:00") didn't work so I settled to this.
  The last part is the most difficult and I'm not able to solve it.
  I have a column with month names (for example) and I want to sum some data only when the month name contains "er". Here is what I thought:</p>
  
  <pre><code>=SUMIF(A6:A16,ISNUMBER(Find("er")),G6:G16)
  </code></pre>
  
  <p>This gives me always 0
  (Note that the last one contains A6:A16 instead of the whole INDIRECT part because I am still testing it in a single sheet.)
  Any Idea what I'm doing wrong?</p>