Hi Annette
I am using this program with my 5th and 8/9th graders. The concept is fun, helpful and TONS of practice. I cannot see where it would help and I would recommend it for all ages that need or want some business math skills anywhere from 4th grade on up. I would worry about using it too early, that might be tricky if they haven’t got their basic skills down, but for my 13yos it was an enjoyable and welcome change of pace and he really enjoyed it. There is also a Sports version and a Bookstore version if your older child is more inclined that way? I would think you will be fine for your 8th grader.
Heidi