Recently, I have had two wonderful websites shared with me filled with virtual manipulatives for mathematics. As a person who has struggled with math her entire life, I understand the need for these tools. Giving students the chance to visualize and manipulate math helps them better understand the problem. Numbers and symbols look like a new language. And, guess what? Math is a language. In order for our students to understand this language, we need to give them pictures and an opportunity to try it out.
The first site comes from Glencoe/McGraw Hill. You can select grade levels, background templates, and different manipulatives. My personal favorite is the Bears in a Boat for the Kindergarten level manipulatives. This also has some really nice drawing tools at the bottom of the screen.A second site is the National Library of Virtual Manipulatives. From this site, you can choose different math subjects for different age levels. For example, you can choose Number and Operations for grades 9-12, or Algebra for grades 3-5. There are excellent manipulatives in each category. Below is is the Geoboard under Geometry for grades 3-5. This provides challenges on the side for students to complete. I only wish it gave some feedback for correct or incorrect answers.
I encourage you to explore these sites. Hopefully you can find some useful tools to help instruct and guide your students through math!