Despite the very mixed reviews, or flat out bad reviews, I decided to try IXL for a month. Day one, DD spent about 10 minutes, said it was too easy (I think that she meant too repetitious) and got up from the computer. Voluntarily getting up from the computer is not a common behaviour around here! I guess it's a bust... or, on second thought, maybe I can use it to keep her off the computer. "If you want to use the computer you must do 15 minutes of IXL first!" Thanks for all the input, good and bad.
