A great resource that gives you math "challenges" that you can send home with students to have them work on with their families! Few materials necessary and very engaging
This blog shares websites for both teachers and students and focuses on a broad range of topics including science, math, geography, and graphic organizers.
An incredible compilation of virtual manipulatives to be used in math instruction -- just choose your grade and topic, and a massive list is provided to give you options of instructional strategies!