In other cases, the same digital economics have spurred entirely new business models, such as "Freemium," a free version supported by a paid premium version. This model uses free as a form of marketing to put the product in the hands of the maximum number of people, converting just a small fraction to paying customers. It's an inversion of the old free sample promotion: Rather than giving away one brownie to sell 99 others, you give away 99 virtual penguins to sell one virtual igloo. (Confused? Ask a child: This is the business model for the phenomenally successful Club Penguin.)
Samantha Morra on 26 Jan 09Nice interactive fraction site.
jodi tompkins on 27 Oct 10Tutorial over Fractions. Includes identifying, renaming, comparing, adding, subtracting, multiplying, and dividing. Great way to reinforce what is taught in the classroom.
