The accuracy of the calculations made by the software, in most cases, it is a matter of faith, as it is impossible to check with other methods the complex calculations that the machine is able to perform in a limited time. But for simple calculations like arithmetic POSSIBLE from the calculator system, verification is almost instinctive. Miscalculator Erik Sandelin and Magnus Torstensson questions with a good dose of irony this process, being a software calculator that unpredictably wrong (slightly) the results. An important feature is to remove the standard Windows calculator and replace it permanently. This mode enters the conceptual domain operates in a much more profound. The uncertainty of the 'certain' mathematical, in fact, as well as offering unprecedented degrees of freedom of reality (accounts lighter, or earn more, depending on the context of the calculation), it is understood by the authors, calling him a 'digital tattoo ', as the standard that s'implementa, namely as the mode in which the' true 'should be understood. If this framework could be applied invisibly to all processes of the machine, you would get, perhaps, a fascinating and endless generation of digital surrealism.