Teacher: Tommy has not been very consistent handing in his homework.
Parent: Tommy comes home and tries to do his homework, but he can never remember how to do it.
Teacher: Have you tried to sit and help him?
Parent: I try but I usually don't remember enough to help him out.
Khan Academy provides free online instructional videos on a wide range of topics from basic addition to lattice multiplication to advanced calculus. They also offer a free app for iPod, iPad, and Android devices.
The videos are simple and give a good overview of the topic with visual samples. The videos could also be a great way for advanced students get a step ahead. By creating an enrichment page on your website you could provide links to relevant video topics and worksheets to test their skills.