3. CHAPTER II: Measurements and Scientific Notations
Learning Outcome 2:
Applied the rules of measurements
and scientific notation in solving
problems.
4. Significant figure is the digits in a
measurement which is read and
estimated on a
scale.
SIGNIFICANT
FIGURES
CHAPTER II: Measurements and Scientific Notations
5. A. To determine the number of significant figures in a number, use the following rules:
1. All non-zero numbers ARE
significant. The number 38.7 has
three significant figures
because all of the digits present
are non-zero.
2. Zeros between two non-zero
digits are significant. 8001 has
FOUR significant figures. The
zeros are between nonzero digits
8 and 1.
3. Leading zeros are not
significant. They are "place
holders." The number 0.74 has
only two significant figures.
0.0012 also has two significant
figures.
4. Trailing zeros to the right of
the decimal are significant. There
are four significant
figures in 97.00.
5. Trailing zeros in a whole are
not significant. Writing just
"3400" indicates that the
zeros are not significant, and
there are only two significant
figures in this value.
6. Trailing zeros in a whole
number with a bar placed on top
of a zero are significant.
"340 ." indicates that the trailing
0̅
zeros are significant; there are
four significant figures in this
value.
7. Exact numbers have an
infinite number of significant
figures. This rule applies to
numbers that are definitions. For
example, 1 meter = 1.00 meters
= 1.0000 meters =
1.0000000000000000000
meters, etc.
RULES FOR SIGNIFICANT FIGURES
CHAPTER II: Measurements and Scientific Notations
6. RULES FOR SIGNIFICANT FIGURES
B. Rounding off significant figures:
To round off numbers, we simply drop all unwanted digits to the right of
the digits that are to be retained and increase the last retained digit by 1 if the
first dropped digit is 5 or greater. It may be necessary to replace dropped digits
by zeros in order to hold the decimal point; for instance, we round off 8351.35
to the nearest hundred as 8400, to the nearest thousands as 8000, and to the
nearest tenths as 8351.4.
CHAPTER II: Measurements and Scientific Notations
7. C. For addition and Subtraction with significant figure:
They should be rounded off to the precision of the least precise
measurement. For example, add or subtract 321.36 and 51.2. First, we
round off 321.36 to nearest tenth,this will give 321.4.
Addition gives us 321.4 + 51.2 = 372.6.
Subtraction gives us 321.4 - 51.2 = 270.2.
RULES FOR SIGNIFICANT FIGURES
CHAPTER II: Measurements and Scientific Notations
8. D. For multiplication and division with significant figure:
The number of significant figures in the result is no
greater than the number of significant figures in the
measurement with the fewest significant figures.
For example, multiply 12.3 by 2.5, longhand
multiplication will give 30.75. The answer should be
rounded off to 31 because 2.5 has two significant figures.
The division will give 4.9 rounded from 4.92.
RULES FOR SIGNIFICANT FIGURES
CHAPTER II: Measurements and Scientific Notations
9. A. Addition and Subtraction of two numbers expressed in scientific notation.
Before adding or subtracting two numbers expressed in scientific
notation, their powers of ten must be equal or convert the numbers to
ordinary decimal form then add or subtract. Convert the answer in
scientific notation. For example, add or subtract 9.87x10^4 and
1.37x10^3, convert one of the two numbers to make their power of 10
equal. 1.37x10^3 = 0.137x10^4. Adding gives 10.007x10^4 =
1.0007x10^5. Subtracting gives 9.733x10^4.
.
OPERATIONS WITH SCIENTIFIC NOTATION
CHAPTER II: Measurements and Scientific Notations
10. B. Multiplication of two numbers expressed in scientific notation.
To multiply two numbers expressed in scientific notation,
multiply separately their decimal parts and their powers of ten,
then add their exponents. Express final answer in scientific
notation.
For example,
(1.25x10^4)(4.98x10^7)= (1.25)(4.98)x10^(4+7)
= 6.225x10^11 or 6.23x10^11
OPERATIONS WITH
SCIENTIFIC NOTATION
CHAPTER II: Measurements and Scientific Notations
11. C. Division of two numbers expressed in scientific notation.
To divide two numbers expressed in scientific
notation, divide separately their decimal parts and their
powers of ten, then subtract their exponents. Express
final answerin scientific notation.
For example,
(5.98x10^7)÷(2.7x10^4) = (5.98)÷(2.7)x10^(7-4)
= 2.21481481x103
= 2.2x103
OPERATIONS WITH
SCIENTIFIC NOTATION
CHAPTER II: Measurements and Scientific Notations