Sumifs across multiple worksheets

[JohnFex]

Hello,

I am trying to 'sumifs' across multiple worksheets, but am failing. Please see the attached sheet and the cell A5 on 'Assistencia' for what I am trying for but I want to calcualte a total of all the months onto the 'assistencia' sheet.

I have looked on the forum and I can see there are very elegant ways of doing this, but I just can't seem to replicate them. I would appreciate any help and also, if anyone has the time, it would be great if you could just breakdown a little what the different parts of the formula refer to as I would love to learn the technique.

Many thanks,


John