Area and Perimeter - A practice site for finding area and perimeter
Billy Bug - a fun game for kids to practice finding coordinates on a graph
Cool Math For Kids - Lots of VERY colorful math game and tutorials for kids.
Find the Quarks - This battleship-like game lets two students practice finding things on a coordinate grid. It's also a way to introduce concepts of quantum physics if you are feeling ambitious.
Interactive Shape Explorer - This online lesson on finding area and perimeter of irregular shapes gives students direct instruction an activity and help.
Math magician - This is a great practice site where students race against the clock to solve math problems.
Prisims - A very visual site on geometric solids.
Rain Forest Maths - This site has hundreds of math activities, all arranged by grade level. Although it is not based on NC curriculum, many standards do overlap.
Robot Guy and the Alien Invaders - a fun math game with multiple players that asks students questions about angles. It is listed for 6th grade but would work for 5th.