has two significant figures, while 
implies that both zeros are significant. [M1.2, P1.1]
are: the meaningful digits in a number. [M1.2, P1.1]
indicate: its precision. [M1.2, P1.1]
do not include: zeros to the left of the first non-zero digit, as in 0.00876. [M1.2, P1.1]
may or may not include: zeros at the end of a number, particularly a whole number, as in 9400. These are ambiguous. [M1.2, P1.1]
are totally unambiguous: in scientific notation, which avoids the need to write down any zeros that are not significant either to the right or to the left of the significant figures. For example, has two significant figures, while implies that both zeros are significant. [M1.2, P1.1]
Copyright 1997, The Open University