Common Core Resources:
https://www.cde.ca.gov/re/cc/ccssresourcesparents.asp
https://study.com/resources/common-core-math-parents
Khan Academy: https://www.khanacademy.org/ (I love Khan Academy and recommend it for testing procedural skills at any level.)
Purple Math: https://www.purplemath.com/ (I used this all the time in middle and high school!)