Cryptarithms vs Lehrer Lämpel

The ability to sum numbers and perform logical reasoning are the only skills required for solving cryptarithms. Nevertheless, these puzzles are often witty and challenging to solve. A cryptarithm is a mathematical puzzle where digits in an arithmetic equality are replaced by letters. It is defined so that distinct letters correspond to distinct digits. Moreover, when the letters are converted back by the original digits, the resulting equality must be valid. The problem is to find the original digits. 90 сryptarithms with their translations to 6 languages are presented. Enjoy!

The app implements the popular number wheels known from many school books; it supports primary school children to practise their skills in basic arithmetic: addition, subtraction, multiplication and division. The learner is given a wheel of twenty segments, grouped into an inner and an outer ring around a pivot element. Half of the segments are pre-filled with numbers. Now, learners need to compute the missing numbers, given the pivot element and the chosen operation (addition, or multiplication). The app offers a training and a challenge mode. In the training mode, pupils can ask Lehrer Lämpel for help at any time. In the challenge mode, a timer of one minute counts backwards (more time is allocated for more difficult tasks); segments have to filled out in the given order. Can you solve the wheel under a minute? -- For the challenge mode, there is a high score table maintaining the top 20 scores. The app supports an unlimited number of randomised exercises, and three levels of difficulty. The app supports English, French and German. Available on the iPad, for iOS9 or later. The app is ad-free. No data is being collected. No web access is required. The high score is maintained locally. Please consider leaving a review. This helps a lot. Thanks!