Significant Figures1

RULES FOR COUNTING SIGFIGS

CaseExamples
value # sigfigs

Zeros between other significant digits are
405
3
significant
807.105
6

Zeros on the right of the first non-zero digit
0.03800
4
are significant
3,6000,000
7

Zeros on the left of the first non-zero digit
0.006
1
are not significant
0.0352
3

Zeros on the right of the last non-zero digit,
47,000
2-5
but to the right of the decimal are ambiguous,
380
2-3
but can be clarified with scientific notation
1.00x107
3

RULES FOR CALCULATIONS WITH SIGNIFICANT FIGURES

126.7
7439.575 4639.753
833 -1542.61
7574.605-> 7574.6 3097.143-> 3097.14

32x87.1x2.6666=7432.3475 167.90/22= 7.6311818
7.4x103 7.6

1Adapted from Coop, D.W., The Camelot Chemistry Primer, Kenndon, Kraistins & Gould Publishers; Temecula, CA. 1992. P.29-31.