Numbers will open Excel files. I tried using it initially but found it too limiting and, I admit, a learning curve. I decided to install Office 2011 instead. But just open Numbers and select the file you want to open. Your Excel files will show up as "openable" when you tell Numbers to open a file. When you go to save the file it will automatically save it as a numbers file. You might loose some excel embedded formulas or functions but I did not have any issues.