When it’s time for some basic calculations and graphing, check out Apple Numbers for the iPad. This app lets you work with Excel or CSV formatted files. You’ll get the basics you’d expect in a spreadsheet, like the ability to generate graphs and work with predefined functions. There are only about 250 functions so you may not have access to your favorite financial or database function but you’ll have many of the basics. Available from Apple, Inc. for $9.99.