This app presents good ways to learn the concepts of adding and subtracting and how they can be thought of as combining and separating. Unfortunately, at the harder levels, it just assesses the students on their ability to memorize rather than to know addition or subtraction. A student may also simply click a bunch of random numbers until they get the correct answer. I would want to use this for my child before they start learning addition and subtraction in written form, but there are other ways to promote these concepts than paying $3 for this app.