What are the odds of a miscalculation in an Arduino?
I don't know the odds for this to occur, and I suspect them to be incredibly low. However, if you're really serious about trying to detect such errors, here's one simple way you could: Perform the exact same calculation twice storing the results independently. If all has gone well, both results will be identical. So if you compare them and they differ, you know something went wrong, and you could repeat the calculations until the results match. While it's theoretically still possible that you miss errors, the odds have now been reduced even further. The downside is of course that you at least double the number of calculations and you have to do additional comparisons, both of which take up further CPU cycles. There are certainly other more elegant solutions.