Parastās daļas

 http://illuminations.nctm.org/Activity.aspx?id=3510

 http://nlvm.usu.edu/en/nav/frames_asid_104_g_1_t_1.html?from=topic_t_1.html

 http://nlvm.usu.edu/en/nav/frames_asid_103_g_1_t_1.html?from=topic_t_1.html

http://www.macibuvideo.lv/c/dalas

https://www.youtube.com/watch?v=6wb-8tYRK-U

http://www.homeschoolmath.net/online/factoring.php