Significant
Figures Rules
What are Significant Figures?
•They are all the numbers in
a measurement that are
known with certainty plus
the first digit that is
uncertain.
Why use Significant Figures?
•Significant figures are
needed in science,
because the tools we use
to measure are not
infinitely accurate.
Significant
Figure
Rules
1. Non-zero digits
and zeros between
non-zero digits are
always significant.
1, 2, 3, 4, 5, 6, 7, 8, 9
are non-zero numbers
– they are always
significant.
0046.78 – the zero’s are
NOT significant
460.708 – the zero’s are
significant because they are
between non-zero numbers.
How many significant figures in the
following numbers?
•36,838
•7,038
•800,005
•036.73
2. Leading
zeros are not
significant.
00467
0.45
0.00245
The zero’s are NOT
significant due to the fact
that they are leading zero’s.
How many significant figures in the
following numbers?
•46,064
•0.004704
•0074,736.04
3. Zeros to the right
of all non-zero digits
are only significant if
a decimal point is
shown.
35000
7370
37000
The above zeros are NOT significant
The below zero’s are significant.
64.0
35000.
7370.
How many significant figures in the
following numbers?
•67.300
•2,800
•9,000
•8090.
4. For values written
in scientific notation,
the digits in the
coefficient are
significant.
6.02 x
23
10
All the number in the
coefficient (6.02) are
significant.
How many significant figures in the
following numbers?
•5.048
-4
•8.00 x 10
2
•4.70 x 10
8
x10
How many SIGNIFICANT
FIGURES are in the following
numbers?
Write you answer in the space
provided.
2 minutes.
1.
83.591
2.
5007
3.
10.005
4.
20 080
5.
1 000 000
6.
0.0012
7.
1.007
8.
196.0
9.
75000.
10.
82000
11.
22
1.52x10
12.
-6
2.00 x10
Multiplying/Dividing with Sig
Figs
• When multiplying or dividing
using significant figures, the
product or quotient will contain the
same number of significant figures
as the number with the least
significant figures.
What is 23.95 x 11.7?
23.95 x 11.7
280.215
Answer with correct Sig. Figs.
280.
Adding/Subtracting with Sig Figs
• When adding or subtracting with
significant figures, the sum or difference
has the same number of decimal places as
the measurement with the least number of
decimal places.
What is 23.96 + 11.7?
23.96 + 11.7
35.66
Answer with correct Sig. Figs.
35.7
Do the following problems with
the correct number of
SIGNIFICANT FIGURES.
Write you answer on the back
of the notes.
1.
24 x 31.8
2.
8.40/4.2
3.
49.1 + 8.001
4.
81.350 - 7.35
5.
0.0056 x 3.227
6.
1007/33.6
7.
20300 – 2878.6
8.
21
(1.5x10 )
x
13
(2.07x10 )
Use the information from these
note to complete the Significant
Figures Worksheet.
Be sure to ROUND properly!!
Be prepared for a QUIZ over
Significant Figures and Density
tomorrow