any math teachers here? or parents of kids with remedial math?

[grasswire]

A sixth-grader in my extended family is going to need some remedial math work over the summer, we've just discovered. It's horrifying that she has coasted without anyone figuring out that she just doesn't understand FIFTH grade math, let alone her current work. Apparently there's no mechanism for the teacher to discover this, as there are no math tests and the kids in her blended-grade classroom have been helping her do her homework -- which hasn't helped her learn to solve problems.

My question: is there some computer game software that could bring her up to speed on 5th and 6th grade math? Fractions, decimals, conversion of fractions to decimals, early geometry, etc.? Or what about workbooks?