This is interesting, I especially like the Scrubbing Calculator. While I am not sure how it would handle math above Algebra 1, I think this could be great for building intuition in Pre-Algebra and Algebra 1, which are the most important years of math education, in my opinion.
I tutor some 11-14 year-olds who are studying these sorts of things, and it's incredible how many of them can look at something like 100/0.08 and have absolutely NO idea what neighborhood the answer should be in. (For example, they might accidentally multiply, get 8, and never think twice that the answer couldn't possibly be 8 because it has to be above 100.) Something like this might be really helpful in building intuition about the relationships between numbers.
I tutor some 11-14 year-olds who are studying these sorts of things, and it's incredible how many of them can look at something like 100/0.08 and have absolutely NO idea what neighborhood the answer should be in. (For example, they might accidentally multiply, get 8, and never think twice that the answer couldn't possibly be 8 because it has to be above 100.) Something like this might be really helpful in building intuition about the relationships between numbers.