Math Is Fun
Math Is Fun: Word Questions: Elementary Addition
Work against a timer as you test your ability to add and to solve word problems. Use number-line clue for help and score points. Fun activity for individuals, small groups, on an entire class.
Lawrence Hall of Science
The Math Page: Skill in Arithmetic: Power of Ten
This website from The Math Page explains and defines basic arithmetic terms and place value concepts. There is even a practice section at the very end of the lesson.