In scientific notation, nonzero numbers are written in the form m × 10 n. or m times ten raised to the power of n, where n is an integer, and the coefficient m is a nonzero real number (usually between 1 and 10 in absolute value, and nearly always written as a terminating decimal).The integer n is called the exponent and the real number m is called the significand or mantissa.

A440 (also known as Stuttgart pitch) is the musical pitch corresponding to an audio frequency of 440 Hz, which serves as a tuning standard for the musical note of A above middle C, or A 4 in scientific pitch notation.It is standardized by the International Organization for Standardization as ISO 16.While other frequencies have been (and occasionally still are) used to tune the first A …