NCTM- National Council of Teachers of Mathematics: This website provides news from NCTM. If you are a member, you can access articles and journals about the latest research in teaching mathematics.
Engage NY: This site contains modules based on the New York Common Core State Standards that teachers can use to help guide their instruction.
Khan Academy: This site contains thousands of videos and practice problems of a variety of mathematics content. Students can use these videos to help support their learning and also use the accompanying practice problems to strengthen their skills. Teachers can also use these videos to implement a flipped classroom.