This educational app supports primary school children (usually from 3rd grade) to practise their multi-column subtraction skills.

The two main subtraction methods, namely, the Equal Additions Method (aka the Austrian Method), and the Decomposition Method are supported.

Easy drag & drop of numbers to the blackboard.

Immediate feedback option where incorrect steps are immediately marked red and where correct steps are immediately marked green.

Pupils can ask Lehrer Lämpel for help at any time. Help first removes an erroneously learner step; if there are no errors, a single step is performed towards the solution.

All teacher steps towards the solution are followed-up with a step explanation as well.

Various degrees of difficulty guided by the number of digits the two numbers can have, and whether borrowing operations are required.

Supports self-defined subtraction tasks and there is a work-sheet, and randomised exercises.

Supports English, French and German.

Available on the iPad, for iOS9 or later.

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