Transcript Sec. 5.3

OBJECTIVES
A
Multiply using
decimal notation.
B Convert from
notation like 45.7
million to standard
notation, and
convert between
dollars and cents.
To multiply using decimals:
a) Ignore the decimal points,
and multiply as though both
factors are whole numbers.
0.8  0.43
2
0.43
 0.8
344
b) Locate the decimal point in
the result. The number of decimal
places in the product is the sum of the 0.43
 0.8
number of places in the factors.
(count places from the right).
0.344
Section 5.3
Ignore the
decimal points
for now.
(2 decimal places)
(1 decimal place)
(3 decimal places)
1
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To multiply any number by 0.1, 0.01, 0.001, and so on,
a) count the number of decimal
0.001  34.45678
places in the tenth, hundredth,
or thousandth, and so on, and
3 places
b) move the decimal
point that many places
to the left.
0.001  (6.4)
0.001  34.45678 = 0.03445678
Move 3 places
to the left.
0.001  34.45678 = 0.03445678
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To multiply any number by 10, 100, 1000, and so on,
a) count the number of
zeros and
100  4.1
1000  34.45678
3 zeros
b) move the decimal
point that many places
to the right.
1000  34.45678 = 34.456.78
Move 3 places
to the right.
1000  34.45678 = 34,456.78
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0.001  (6.4)
0.0001  721.4
1000  (2.3046)
100  4.1
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Naming Large Numbers
1 hundred = 100 = 10  10 = 102
EXAMPLE:
2 zeros
1 thousand = 1000 = 10  10  10 = 103
3 zeros
1 million = 1,000,000 = 10  10  10  10  10  10 = 106
6 zeros
1 billion = 1, 000,000,000 = 109
9 zeros
Convert the number
in this sentence to
standard notation:
The estimated world
population as of July
2005 was 6.4 billion
people.
6.4 billion = 6.4  1 billion
1 trillion = 1,000,000,000,000 = 1012
12 zeros
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Dollars to Cents Conversions
To convert from dollars to cents, move the
decimal point two places to the right and change
the $ sign in front to a ¢ sign at the end.
Cents to Dollars Conversions
To convert from cents to dollars, move the
decimal point two places to the left and change
the ¢ sign at the end to a $ in front.
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Homework:
Problems 33, 41, 45 - copy the
problem, multiply showing all work.
Problem 55 – copy the problem and
give the answer (146₵ = $1.46)
Problem 59 – copy the number in
words, then give the number is
standard notation.
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