Significant Figures

Significant figures allow us to appropriately express the degree of confidence in a number.
A significant figure or digit is any digit used in a number except:

Zeros that are used to locate the decimal point, such as:

				0.05	0.0003	  0.00235

Zeros that do not have any nonzero digits on their left, such as:

				0.5	0.515	  0.25

How to Designate Significant Digits
Do the numbers 5000 and 5000. imply the same significance? When written 5000. there are four significant digits while 5000 could contain one, two, three, or four significant digits.

How should you write 5000 to two significant digits? Using scientific notation this would be

				     5.0 x 10^3

The nomber of significant figures used implies a certain maximum error range. Three , four, and five significant figures imply maximum errors of 1%, 0.1%, and 0.01% respectively. For arithmatical operations, the rules for combining significant figures are as follows:

Addition and subtraction-- line up decimals and retain the least significant place.
Multiplication and division-- the number with fewest digits excuding exact conversion factors determines is used.