If a raised to the power of n is equal to x (a>0, and a is not equal to 1), then the number n is called the logarithm of x with a as the base, and is written as n=logax. Among them, a is called the base of the logarithm, x is called a real number, and n is called "logarithm of x with a as the base".

In b=lgN, the antilogarithm is to find the corresponding real number N with the known logarithm b, and 10^b=N, so N=lg-1b=10^b, so we can directly calculate 10^b.

Removing the redundancy in the expression 4 + 1/(2 + 1/(6 + 1/7)) yields the abbreviated notation [4; 2, 6, 7].