IXL – Maths Practice Site
Practice makes perfect, and IXL makes math practice fun. With unlimited math questions in more than 1,000 topics, students improve their skills and confidence and always have new challenges to meet. All you need to do is click a grade level to get started.
Some grade levels have a speaker next to the questions and answers that will read the text to the student. Very clear graphics, and simple for students of all ages to use.
Whilst you can subscribe to the site, and gain additional functionality (similar to Mathletics and Intrepica), the site seems to function extremely well as a standalone.