Enigeo is a great way to learn countries, capitals and flags around the world in a fun way. You can either answer questions about the countries in a highly customizable quiz or you can just explore the world and learn about different countries. best of all- it's FREE!
Lots of activities to help explain different operations with fractions. Includes equivalence, addition and subtraction and comparing. Has tutorials as well as activities to test knowledge.
A great site that has a new mini maths challenge every day. Suitable for grades 4+. Great to show on the IWB at the start of a Maths lessons to tune kids in.
Covers a wide variety of Maths topics and provides answers.