Excel Basics
Following articles explain the Excel fundamentals you should know before moving on to advanced concepts.
Excel Worksheet
Excel Workbook
Excel Ribbon
Excel Functions
Excel functions reference link below provides overview of excel functions. You can click on individual functions to learn more about them with example.
Excel functions reference
The following post is regarding 10 commonly used Excel functions :
Top 10 must know Excel functions
Excel Data Analysis
Following excel posts are regarding data analysis features provided by Excel:
Excel Pivot Table
Sorting data in Excel
Others
Excel Interview Questions