Adi gives lots of clear instructions and then turns kids lose to explore on their own. This was my favorite. Kristina liked it too, but it does challenge students and progressively gets harder. With Adi's help, children can select from Numbers, Calcuation, Measurement, Patterns, and Geometry. Each topic has 5 sections within that vary in activity and progress in difficulty.
Children can start at the beginning or start anywhere they please.
Whole apples indicate they haven't tried that section yet, and an apple core indicates they've successfully completed it. There are so many activities inside each topic, it's impossible to cover them all. Measurement includes length, capacity and mass, money, time, and calendar. I found all of these exercises to be well-designed with good instructions to help younger ones move through them. Sierra does a good job incorporating motivation and feedback for kids to keep them interested in continuing on.