Length Subtraction app for iPhone and iPad

This is a cool Maths application using which a child can learn and practice the whole number and decimal subtraction concept exactly the same way the child does it on paper. A magic alien in the application gives different length subtraction examples to practice. It monitors the child’s progress and paces the complexity of the problem according to the performance of the child, starting from simple whole number length subtraction (e.g. 5m - 3m) to length subtraction involving different units (e.g. 16 m 10 cm - 8 m 36 cm) and then moves to decimal subtraction (e.g. 5.32m - 2.15m). In case a mistake is made (e.g. wrong borrowing), the magic alien is able to pin-point the exact mistake. If the child is unable to make progress on a given problem, he/she can touch the magic alien and the alien walks through the detailed solution of the same problem in an animated way - giving the exact steps similar to how it is done on the paper.
The child can touch the Report Card icon to see the progress. This way the child can continue to practice the subtraction and decimal subtraction concept in a way he/she does on paper with the super power of our magic alien.
Have fun, children!