IIRR mine was 6 when we watched this, and his maths level was more than needed. My guesstimate would be that the course would be enjoyed by an 11yo (or older child or adult of course!) who was enthusiastic but not necessarily advanced, or by a younger child who was advanced.
I think there's a lot to get out of it at a variety of levels. DS and I have both enjoyed them. DS is 6 and operating at a level of second to sixth grade, depending on your lens. He is getting a lot less out of it than I am, and at a different level, but still loving it. I bet that if our schools don't squeeze the love of math out of him, by the time he's 10-11, he'll enjoy them again.
