The SumifS function is a new function that was brought in in Excel 2007. Essentially, it is an upgrade for the SumIf function in the sense that it allows you to sum numbers based on more than one criteria. I plan to do another post on this to show you how to use SumIFS with dates.
Have a look at the video below to get a sense of how it works and as always there is a file underneath for you to practise on.
Click on this link to download an Excel file you can practise on: sumIfS_demoFile