BBC
Bb Ci: Review Significant Digits
BBCi presents a test prep review ("revision") section on significant digits and on approximating an answer by rounding in order to work with an easy number. Click on "Test Bite," on the last page to get an interactive quiz.
Fun Brain
Fun Brain: Place Value Puzzler
An engaging and fast-paced game from FunBrain, where players activate their knowledge of place value and rounding. Numbers range in difficulty from easy to hard. However, for those who are up for a more serious challenge, there's also a...