Transcript PERCENT - lesson 11

0011 0010 1010 1101 0001 0100 1011
Lesson 11
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WHAT DOES PERCENT MEAN?
0011 0010 1010 1101 0001 0100 1011
• Percent means “out of 100”
• EXAMPLE:
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212 = 2.12
60 = 0.6
100
100
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HOW TO CHANGE PERCENT TO
A FRACTION
0011 0010 1010 1101 0001 0100 1011
• Make an equivalent fraction out of 100
6 = 30
20 100
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• Numerator is the answer with a % sign.
x20
TRY THESE
2 = 40
5 x20 100
x25
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75
=
4 x25 100
x20
÷3
6
40
2
=
=
15 ÷3 5 x20 100
0011 0010 1010 1101 0001 0100 1011
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HOW TO CHANGE A DECIMAL
TO PERCENT
0011 0010 1010 1101 0001 0100 1011
• Place Value
0.415
hundredths
EXAMPLE:
x10
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thousandths
tenths
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9 = 90
0.9 =
= 90 %
10 x10 100
HOW TO CHANGE DECIMAL TO
PERCENT
0011 0010 1010 1101 0001 0100 1011
• Why do we say move the decimal two
places to the right?
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• Multiply by 100 because percent means
“out of 100”
0.90 = 90 %
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TRY THESE
0011 0010 1010 1101 0001 0100 1011
0.7
0.56
0.349
1.26
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HOW TO CHANGE PERCENT TO
A FRACTION IN LOWEST
0011 0010 1010 1101 0001 0100 1011
TERMS
EXAMPLE
÷2
÷2
9
36
18
36 % =
=
=
100 ÷2 50 ÷2 25
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USE DIVISIBILITY RULES TO MAKE THIS
FASTER
HOW TO CHANGE PERCENT TO
A FRACTION IN LOWEST
0011 0010 1010 1101 0001 0100 1011
TERMS
EXAMPLE
÷25
5 = 11
125
125%=
=
4
100 ÷25 4
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Why do we say move the decimal two places to
the left?
We are dividing by 100 because percent is
“out of 100”
HOW TO FIND THE PERCENT OF
A NUMBER
0011 0010 1010 1101 0001 0100 1011
EXAMPLE
25 % OF 40
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1) Change Percent to a fraction and multiply
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40
x
40 =
25 % =
= 10
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HOW TO FIND THE PERCENT OF
A NUMBER
0011 0010 1010 1101 0001 0100 1011
2) If both numbers end in 0, multiply the first digits
together
20 % OF 60
2 x 6 = 12
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DETERMINE THE NUMBER
0011 0010 1010 1101 0001 0100 1011
50 % OF A NUMBER IS 10
50% = 10
10 ÷ 50% = ?
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÷
10 2 = ?
_____
x
10 x
2
1
= 20
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EXAMPLE
0011 0010 1010 1101 0001 0100 1011
60 % OF A NUMBER IS 42
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WHAT “PERCENT OF”
QUESTIONS
0011 0010 1010 1101 0001 0100 1011
WHAT PERCENT OF
80 IS 16
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WHAT “PERCENT OF”
QUESTIONS
0011 0010 1010 1101 0001 0100 1011
WHAT PERCENT OF
80 x _____ = 16
80 IS 16
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WHAT “PERCENT OF”
QUESTIONS
0011 0010 1010 1101 0001 0100 1011
WHAT PERCENT OF
80 x _____ = 16
16 = ?
80
80 IS 16
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WHAT “PERCENT OF”
QUESTIONS
0011 0010 1010 1101 0001 0100 1011
WHAT PERCENT OF
80 IS 16
80 x _____ = 16
REDUCE TO
16 = ? LOWEST
TERMS
80
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WHAT “PERCENT OF”
QUESTIONS
0011 0010 1010 1101 0001 0100 1011
WHAT PERCENT OF
80 IS 16
80 x _____ = 16
REDUCE TO
16 = ? LOWEST
TERMS
80
2 = 0.2 20 %
=
10
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Try this
0011 0010 1010 1101 0001 0100 1011
Microwave costs $119.00
• Sale: 15% regular price
• Find the change in Price
• Find the sale Price
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Microwave costs $119.00
Sale: 15% regular price
0011 0010 1010 1101 0001 0100 1011
• Find the change in price
$119 x 0.15 = $17.48
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Microwave costs $119.00
Sale: 15% regular price
0011 0010 1010 1101 0001 0100 1011
• Find the sale price
$119 x 0.15 = $17.85
$119 - $17.85 = $101.15
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or
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$119 x 0.85 = $101.15
TRY THIS
0011 0010 1010 1101 0001 0100 1011
A Frisbee costs $5.98 after a 20% discount.
Find the original price
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HINT: This is the same as “% of a number”
question
A Frisbee costs $5.98 after a 20%
discount.
0011 0010 1010 1101 0001 0100 1011
Find the original price
__________
x
80% = $5.98
$5.98 = $7.48
0.8
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TRY THIS
0011 0010 1010 1101 0001 0100 1011
DVD is regularly $130 is on sale for $89.
What was the discount ( in %)
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DVD is regularly $130 is on sale for
$89.
0011 0010 1010 1101 0001 0100 1011
What was the discount ( in %)
Original - New
Original
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$130 - $89 = $41 = 31.5 %
$130
$130