Significant Figures. Rule 1: All non-zero digits are significant. Ex:48.7 2962 = 3 SF = 4 SF

Significant Figures

Rule 1:All non-zero digits are

significant.

Ex: 48.72962

= 3 SF= 4 SF

Rule 2:Zeros in the middle of a

series of numbers are significant.

Ex: 203490,702 50,008

= 3 SF= 6 SF= 5 SF

Rule 3:Zeros in front of a series of

numbers are not significant.

(They are being used as place holders to insure the correct number of decimal places.)

Ex: 0.0080.4730.0305

= 1 SF= 3 SF= 3 SF

Rule 4:Zeros to the right of a decimal are significant.

Ex: 3.00437.000

0.0050700

= 3 SF= 6 SF= 5 SF

Rule 5:

Zeros at the end of a number that are

followed by a decimal are significant.

Ex: 2000. = 4 SF

Rule 6:Zeros at the end of a number that does not have a decimal are not considered to be significant.

(They may be significant, but we do not have enough information to be

sure.)

Ex: 2000assume 1 SF

Atlantic Side:decimal absent

80200 400000 32105 700

Pacific Side:decimal present

0.0019 65.01 0.0300 700.

Atlantic – Pacific Rule

2 SF4 SF3 SF3 SF

3 SF1 SF5 SF1 SF

Pacific Rule - If a decimal is PRESENT start counting with the first non-zero digit from the

left.

Atlantic Rule – If the decimal is ABSENT start counting with the first non-zero digit

from the right.

Rules for doing calculations

The answer to a set of calculations can not be more accurate

than the least accurate value used in the calculation.

Multiplication and Division

The number of significant figures in the answer is equal to the lowest number of significant

figures used in the calculation.

Ex 1: 20.7 x 8.436 = 174.652this will be reported with 3 SF as 175

Ex 2: 8.340/4.2 = 1.985712this will be reported with 2 SF as 2.0

Addition and SubtractionUse the same number of decimal places as the least accurate value.

(smallest number of decimal places)

Ex 1: 49.1 + 8.001 = 57.101This will be reported as 57.1

Ex 2: 240 – 71.3 = 168.7Round to the tens place and report as 170