Term
Rule 1: Nonzero integers... 

Definition
...are always significant.
(ex) 23.4g and 234g both have 3 Sig Figs 


Term

Definition
...are those bounded on both sides by nonzero integers.
...are always sigmificant.
(ex) 20.05g has 4 SF
(ex) 407g has 3 SF 


Term

Definition
...are those NOT BOUNDED on the LEFT by nonzero integers.
...are never significant.
Such zeros just set the decimal point.
They always disappear is the number is converted to scientific notation.
(ex) 0.04g has 1 SF
(ex) 0.00035 has 2 SF 


Term
Rule 4: Trailing zeros... 

Definition
...are those bounded ONLY ON THE LEFT by nonzero integers are not significant UNLESS A DICIMAL POINT IS SHOWN.
if decimal point shown, ALWAYS significant.
(ex) 45.0L has 3 SF but 450L only has 2 SF (unless there is a line over the 0)
If you wish to show for shure that, say, 150 has 3 SF, change to scientific notation (1.50 * 10^2) 


Term

Definition
...are those not obtained by measurement but by deffinition or by counting small numbers of objects.
...have unlimited number of sig figs.
(ex) in C=2πr 2 is a defined quantity (cannot be any other #) so it has no effect on # of sig figs in answer.
(ex) If you count 15 pennies, that mumber is exact because there cannot be part of a penny (15.3 pennies) 


Term
Rule 6: In calculations involving only multiplication or division of measured quantities... 

Definition
...the # of sig figs in the answer is the same as the FEWEST possessed by any measurd quantity in the calculation.
(ex) 130.8 * 15.2 * 2.3 = 4572.768 when done by a calculator. answer should have 2 sig figs and be shown as 4.6*10^3 


Term
Rule 7: In calculations where measured quantities are added or subtracted... 

Definition
...the final answer can have only one "uncertain" figure, so it stops at the decimal place on the right that any of the data first stops.
(ex)
46.6
+ 5.72
The answer would have to be rounded to the 10's place because that is where the # w/ the least decimal places stops.
(ex)
38.0
 7.44
The answer would be rounded to the ones place. 

