The natural logarithm is the logarithm with the constant e as the base, and it is denoted as lnn(n >；; 0)。 It is of great significance in physics, biology and other natural sciences, and is generally expressed as lnx. Logx is also commonly used in mathematics to represent natural logarithm.

Mathematics pays attention to regularity and aesthetics, but the basic constants such as pi and natural logarithm e are so chaotic, just like two "mathematical ghosts". People can't find the number variation law of π and E, and the possible reasons are as follows: for example, people used decimal system, while the ancients used hand index. Because there are ten fingers, they set the decimal system. Binary is the simplest decimal system in the universe, and it also conforms to the theory of Yin and Yang. 1 is positive and 0 is negative.

For another example, when people compare π and E with those regular numbers, they think that E and π are disordered, so the problem of "reference" is involved. Then, if both π and E are converted into the simplest binary, and the two chaotic numbers π and E are compared with each other, some numerical laws will be found. The first 17 of the fractional part of e and the 5th-21of the fractional part of π are just in reverse order, so it may not be a coincidence that the order is so long.