When you are filling out your expenses claim remember Benford's Law
Everyone knows that our number system uses the digits 1 through 9 and that the odds of randomly obtaining any one of them as the first significant digit in a number is 1/9. (First significant digit means we ignore zeros.) This works well for fake data generated with a random number generator or the type of data an embezzler would create. With naturally occurring data this generally isn't true. The odds of obtaining a 1 for the first significant digit of a number are much higher than the odds of obtaining any other digit as shown by Benford's Law...has been used as a method for spotting fraudulent accounting data by looking at the first significant digit of each data entry and comparing the actual frequency of occurrence with the predicted frequency. Most white collar criminals are unaware of Benford's law and will use each digit about 10% of the time for the first significant digit in a number.