Importance of Spreadsheet
Spreadsheet is full of powerful tools to boost performance. I guess all members in the community know how relevant it is in accounting/finance/auditing field. Then, if you are already familiar why not upgrade your knowledge.
If you are the beginner check Slaying Excel Dragon 1 - 50+
Slaying Excel Dragon
Personally I have been using Excel Is Fun and find it easy to understand.
Thank you, I will try it.