Google Sheets is an online spreadsheet app that lets you create and format spreadsheets and simultaneously work with other people. Here's what you can do with Google Sheets:

• Import and convert Excel, .csv, .txt and .ods formatted data to a Google spreadsheet
• Export Excel, .csv, .txt and .ods formatted data, as well as PDF and HTML files
• Use formula editing to perform calculations on your data, and use formatting make it look the way you'd like
• Chat in real time with others who are editing your spreadsheet
• Create charts with your data
• Embed a spreadsheet — or individual sheets of your spreadsheet — on your blog or website

What about Add Ons?

Add-ons run inside Google Sheets, Docs, and Forms. They are tools built by developers that literally add on capabilities to your documents or spreadsheets. You can use add-ons to do more tasks within an application. For example, the Flubaroo add-on helps you quickly grade and analyze online assignments and assessments, as well as email scores to students!