The exercises maybe simple but you will be surprised how difficult it can be to push the numbers around in the right way to build the solution of the respective exercise and move this number to the correct field. You will need to add or subtract values and make use of the various operator fields to solve all of the 40 exciting levels. Mostly all of this at once! Cudgel your brain and relax to the beautiful sound at the same time.
However – we don’t mind if you want to use a calculator for the exercises… ;o)