Hi, what do you want to do?
Khan Academy
Khan Academy: Add and Subtract Fractions Word Problems
Practice solving fraction addition and subtraction word problems. The fractions in these problems have unlike denominators. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or...
University of Colorado
University of Colorado: Ph Et Interactive Simulations: Expression Exchange
An interactive simulation that teaches about equivalent, evaluating, and simplifying expressions through games and exercises building coin expressions. This simulation can either be downloaded or played online and includes handouts,...
Calculator Soup
Calculator Soup: Scientific Notation Calculator
Use this calculator to add, subtract, multiply and divide numbers in scientific notation, E notation, or engineering notation. Answers are provided in three formats: scientific notation, E notation, and engineering notation.