Here are some fun and interactive websites you can use at home or on the go :)!
Language Arts/Word Study:
http://www.abcya.com/third_grade_computers.htm- practice synonyms/antonyms, spelling, word puzzles and sorting games
http://www.storylineonline.net/ - listen to stories being read by a number of famous celebrities
http://www.funbrain.com/FBSearch.php?Grade=3 - Word play games and activities (math also)
http://pbskids.org/games/reading/ - Word work activities and games
http://www.readingrockets.org/article/word-study-new-approach-teaching-spelling - tips and strategies which help students to become better readers
http://www.pbs.org/parents/education/reading-language/reading-milestones/second-and-third-grader-language-development-milestones/second-and-third-grader-activities-games/- Third grade activities and games
http://www.education.com/activity/third-grade/reading/- various downloadable, free literacy based activities
Math:
http://www.mathplayground.com/grade_3_games.html
http://www.math-play.com/3rd-grade-math-games.html
http://www.abcya.com/third_grade_computers.htm
https://splashmath.com/math-skills/third-grade?gclid=CMvJ3ILz4c4CFQNkhgodGk8Bdw