I have used Aleks with my daughter as a supplementary program at home and it's been very helpful in assessing where she really is and allowing her to learn at her own pace.
In a nutshell, it's an assessment and learning program that first does a quick assessment of a child's knowledge and then presents math lessons that they have the base knowledge to learn. As the student works through the program, they are given as few or as many questions in each subject area as they need to "master" the lesson. It was developed by mathematicians, statisticians, and computer scientists @ UC Irvine. It's a very interesting approach. It definitely needs an in-person teaching component.
Three things I think your principal would like:
(1) The teacher can track the progress and "attendance" of each student easily with their online reporting.
(2) It is by grade and has a way for you to check how each child is doing on subjects as aligned to your state's standardized testing.
(3) For those children who are behind, it allows them to pick up those skills that they missed somewhere along the way that are preventing them from learning later skills and for those children who are ahead, it allows them to progress at their own pace. Both of these will help the school by increasing standardized test scores.
For the record, I know that "teaching to the test" is considered the bane of modern schooling; however, this is the world we live in and that is what the principal is going to be motivated by.www.aleks.com
is where you can find it. There is an independent use contract, too, that is very reasonable - only $20.00/month.
Best of luck!