Editor: AlphaMaths is a totally free program which is user friendly, colorful and easy to use. Note that you MUST have the JRE (Java Runtime Environment) installed for this program to work. The JRE is also totally free.
AlphaMaths has a huge variety of worksheets. In addition to the 20+ worksheets included with the program more worksheets are freely available at the alphamaths.org website. Worksheets that come with the program include addition, subtraction, multiplication and division of whole numbers and fractions as well as Times Tables, decimals and more. Most of these have various options to give a wider range of difficulties. Worksheets can be made by the user with lots of support for making worksheets available in both the help section and on the alphamaths.org website.
Sums in worksheets are automatically generated and then marked. While doing sums you get a detailed breakdown of your progress and results.