Click on cell C2 and apply COLUMNS Formula. Select the column cells you will highlight here I select range B2B13 and then click Home Conditional Formatting New Rule. As we wish to sum every nth column we used a formula combing three Excel functions.
You can also use the Fill command to apply a formula in the whole column or row without dragging AutoFill handle.
In this case we entered sum then selected the Qtr 1 and Qtr 2 columns. If you dont want to use the shortcut keyboard you can use the Fill feature in Excel to apply a formula in an entire column or row. Firstly select the whole column and enter the formula to the first cell ie. Hold the left click of the mouse drag the mouse down to the end of the page.