The National Library of Virtual Manipulatives (http://nlvm.usu.edu/en/nav/vlibrary.html) is a math resource provided by Utah State University. Here you and your students have access to a large (almost unlimited) number of virtual math manipulatives. The manipulatives are categorized by grade level as well as the five standards of mathematics: number & operations, algebra, geometry, measurement, and data analysis & probability. If you have Spanish or French speaking students, they can select to read the site in their first language.
Electronic whiteboard users or even facilitators with only a single computer and LCD projector can use these resources to demonstrate how to use the classroom manipulatives or as whole group instruction of the concept.
If math is hard or you are stuck on a problem, it sometimes helps to see a picture of the problem. In math class, your teacher may have manipulatives (hands-on objects) that you can move or change to help you understand the problem. Here is a link to virtual (online) math manipulatives just like the ones you may use in class. You can also select Spanish or French at the bottom of the page to read the instructions in your first language.