Download Significant Figures notes

Name ___________________________________ Period _____ Date ________________________
Significant Figures

____________ _________________: digits that represent a marking on a scale or non-blinking number of a
display

___________________ (estimated) digits: digits that represents the space between the marks on a scale or the
blinking number on a display
Pacific/Atlantic Rule
Step 1. Ask yourself: Is the decimal point present or absent?
Step 2. Determine which way to start counting.
P
A
C
I
F
I
C
A
T
L
A
N
T
I
C
If the decimal point is present start counting from the LEFT.
If the decimal point is absent start counting from the RIGHT.
Step 3: Start counting on Pacific or Atlantic side from the first NON-ZERO number. Count all numbers after the first nonzero number including zeros.
EXAMPLES:
a) 1234 = __________ significant figures
b) 1204 = __________ significant figures
c) 0.00234 = __________ significant figures
d) 1230 = __________ significant figures
e) 1234.0 = __________ significant figures
Name ___________________________________ Period _____ Date ________________________
Addition/Subtraction Rule
When working with numbers that have a certain number of significant figures it is often necessary to add or
subtract these numbers. When doing so, you must keep track of the number of significant figures the answer
will have.
The rule for addition and subtraction for significant figures is simple:
When quantities are added or subtracted, the number of decimal places in the answer is equal to the
number of decimal places in the quantity with the smallest number of decimal places.
Examples: #1-3 on Significant Figures WS Part B.
1. 903 +12 =
903 = ____________ decimal places
12 = _____________ decimal places
Answer should have ______________ decimal places
Answer = _____________________
2. 0.00125 + 0.3254 =
0.00125 = ____________ decimal places
0.3254 = _____________ decimal places
Answer should have ______________ decimal places
Answer = _____________________
3. 0.00874 + 0.000125 =
0.00874 = ____________ decimal places
0.000125 = _____________ decimal places
Answer should have ______________ decimal places
Answer = _____________________
Name ___________________________________ Period _____ Date ________________________
Multiplication/Division Rule
When working with numbers that have a certain number of significant figures it is often necessary to multiply
or divide these numbers. When doing so, you must keep track of the number of significant figures that the
answer will have.
The rule for multiplication or division for significant figures is very simple:
When quantities are multiplied or divided, the number of significant figures in the answer is equal to
the number of significant figures in the quantity with the smallest number of significant figures.
Examples: #1-3 on Significant Figures WS – 2 Part B.
1. 4.52 x 5.012 =
# of significant figures in 4.52 = _____________ significant figures
# of significant figures in 5.012 = ____________ significant figures
Smallest # of significant figures = ____________ significant figures
# of significant figures in answer = ___________ significant figures
Answer = _______________
2. 0.00120 x 3.2510 =
# of significant figures in 0.00120 = _____________ significant figures
# of significant figures in 3.2510 = ____________ significant figures
Smallest # of significant figures = ____________ significant figures
# of significant figures in answer = ___________ significant figures
Answer = _______________
3. (78.01)/2.01 =
# of significant figures in 78.01 = _____________ significant figures
# of significant figures in 2.01 = ____________ significant figures
Smallest # of significant figures = ____________ significant figures
# of significant figures in answer = ___________ significant figures
Answer = _______________