1. All About Significant Figures By Dr. Chirie Sumanasekera
(SigFigs)
CHEMISTRY
Chapter-2
By Dr. Chirie Sumanasekera
8/29/2018

2. What are Significant Figures??
The significant figures of a number are the number of important single digits in a measurement.
When we study the Sciences, it is neccesery to be able to locate the significant figures in a given measurement or number.
There are 6 rules associated with figuring out significant figures of a number and different rules to figure out how to do addition/subtraction and multiplication /division.
Therese are discussed further….

3. 6 Rules of Significant Figures (Sig-Figs)
All non-zero numbers are always significant. (EX: contains five sig-figs)
Any zeros between significant figures are significant (*zeros between sig-figs are highlighted. EX: contains seven sig-figs, 8.05 contains three sig-figs)
All final zeros to the right of a decimal and at the end of the number are significant. (**Final zeros are underlined. EX: contains six sig-figs, contains four sig-figs)
Place-holder zeros are NOT significant. To remove a placeholder zeros, numbers are written in scientific notation. (EX: contains five sig-figs, contains two sig-figs)
Counting numbers and defined constants have an infinite number of significant figures. (EX: The number of fingers in both your hands is 10. Because this number is precisely 10, you can write it as ….. with an infinite amount of zeros. Thus, this quantity has an infinite number of sig-figs)

4. Other Sig-Fig Rules: ADDITION AND SUBTRACTION:
The answer should be rounded off so as to contain the same number of decimal places as the number with the least number of decimal places. In other words, an answer can be only as accurate as the number with the least accuracy.
Thus: = Rounded off to 48.7
MULTIPLICATION AND DIVISION:
The answer should be rounded off to contain the same number of digits as found in the LEAST accurate of the values.
Thus: x = Rounded off to 18.06