I recommend 3 sites for online academic practice in multiple content areas.
IXL.com can be purchased for an individual or a family with access to multiple content areas. You can try 10 problems for free. It allows students to work on specific skills. Math grades covered range from kindergarten to precalculus!
Here is a link to handouts to help you access Khan Academy which covers a wide range of math grade levels and other content areas, and the ACCUPLACER practice app to prepare for college placement tests.