# significant digits

Significant digits, also called **significant figures**, are the digits that express
a number to a desired accuracy. The significant digits of a given number
begin with the first non-zero integer digit or, if this number is less than
unity, with the first, zero or non-zero, decimal digit. They end with the
final, zero or non-zero, decimal digit; the final zero or zeros of an integer
may or may not be significant. For example, 2.871828 to six significant
figures is 2.87183 (6 s.f.); to three significant figures it is 2.87 (3
s.f.). See also decimal
place.