mathildr is a multi-award-winning learning material that supports children in developing a flexible mental representation of numbers. This term refers to mental pictures of quantities which can be modified in the mind. It is a prerequisite for mental arithmetic.The inclusive app allows a barrier-free numbers representation for all learners and is used in the pedagogical work as a supporting tool.The use of the tablet app requires the guidance and accompaniment of an adult. At www.mathildr.com you can find information on how to use the app.⢠new design⢠results of plus and minus tasks can be displayed⢠improved minus function