There are hundreds of math sites. These are a few that my I used to help me get better at math. Some are free, some are not.  

IXL Math - Offers a wide variety of skills to chose from.  Daily free practice limit of 20 problems.  The full version has unlimited practice and offers alignment to state and common core standards.  

Math is Fun - Free site that offers mini lessons and games in kid friendly formats.

Cool Math - This site is just a lot of learning games.  It can take a while to figure out what game to play.  But they're fun!