Is the logarithm in mathematics, lg is the writing of logarithm (called common logarithm) based on 10.

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The specific explanation is as follows:

If the x power of a is equal to n (a >; 0, and a is not equal to 1), then the number x is called the logarithm of n with a as the base, and is recorded as x=logaN. Where a is called the base of logarithm and n is called real number.