title: Excel formula to reference 'CELL TO THE LEFT'
body: <p>I'm trying to do conditional formatting so that the cell color will change if the value is different from the value in the cell left of it (each column is a month, in each row are the expenses on certain object. I want to monitor easily changes in prices over months.)</p>
  <p>I can do it per cell and format-drag it, but I would like a general formula to apply to the whole worksheet.</p>