Identify the number of significant figures in each of the following measurements.

Rules for Zeroes

Rule

Examples

Zeros appearing between nonzero digits are significant

40.7 L has three sig figs

87 009 km has five sig figs

Zeros appearing in front of nonzero digits are not significant

0.095 987 m has five sig figs

0.0009 kg has one sig fig

Zeros at the end of a number and to the right of a decimal are significant

85.00 g has four sig figs

9.000 000 000 mm has 10 sig figs

Zeros at the end of a number but to the left of a decimal may or may not be significant. If such a zero has been measured, or is the first estimated digit, it is significant. On the other hand, if the zero has not been measured or estimated but is just a placeholder, it is not significant. A decimal placed after the zeros indicates that they are significant.

2000 m may contain from one to four sig figs, depending on how many zeros are placeholders. For measurements given in this text, assume that 2000 has one sig fig.

2000. m contains four sig figs, indicated by the presence of the decimal point

Scientific notation - All digits expressed before the exponential term are signicant.