I too have worked for Sylvan as both a teacher and a director, and I can say that it definitely does work. SHowever, it is expensive and I personally would not use it for summer enrichment. Lots of people do, but as an educator I feel that you really want to make learning more authentic - something real life. Sylvan is really best for when children need to catch up and need a program specific to their needs to fill in the gaps. Instead, I would just find ways to incorporate math and reading into what she does at home - are there educational summer camps she could go to or fun games you can find. You could also ask her teacher for ideas. I don't know a lot about kumon, but the few things I have heard made it sound like it was a lot of repetition and worksheets (while this works, it's not the best way to make her love learning).