WARM UP # 8: Fractions, Decimals & Percent
Write each fraction as a decimal and percent.
Fraction
1) 1/
2) 3/
3) 1/8
4) 7/10
5) 7/
9
6) 3/
5
7) 2/
3
Decimal
Percent
Take
out
a
Calculator!
Correct Homework
If you did not write your full name, date,
and period on your paper take off 1 point.
If you did NOT write each problem -3
points!
If you did NOT write the work next to
each problem -3 points!
Take off 1 point for each problem not
done.
Put your score on your paper out of 10.
Percent
Shortcuts
Method 1: Use place value.
0.2 =
2 = 20 = 20%
10
100
Method 2: Multiply by 100
*Move the decimal 2 places
to the right.
0.2 = 0.20 = 20%
Divide by 100 *Move the decimal 2 places to the left.
218
218% =
= 218
100
20% = 20
100
= 20
100
100
= 2.18
= 0.20
Method 1: Write an equivalent fraction with a
denominator of 100.
40
2 x20
=
= 40%
5 x20
100
Method 2: Write the fraction as a decimal.
2 = 2 5 = .40 = 40%
5
Put the percent over
100 and reduce.
52
52% = 100
13
=
25
4
DECIMALS
1) 0.3
2) 0.41
3) 1.13
ANSWER
DECIMALS
3
10
41
100
4) 0.861
5)
0.35
13
1
100
6)
0.001
ANSWER
861
1000
35
100
1
1000
FRACTIONS
1) 5
8
3
2)
16
5
3)
10
ANSWER
FRACTIONS
2
4)
0.625
11
9
0.1875 5)
6
3
6)
0.5
5
ANSWER
0.18
1.5
0.6
PERCENTS
ANSWER
1) 50%
50 1
100 2
2) 29%
29
100
3) 129%
129
29
1
100
100
PERCENTS
4) 3%
5) 37.5%
6) 25%
ANSWER
3
100
37.5 375 3
100 1000 8
25 1
100 4
Fraction
4
5
16 4
100 25
9
1000
Decimal
Percent
0.8
80%
0.16
16%
0.009
0.9%
Fraction
Decimal
Percent
7
100
0.07
7%
3
10
0.3
30%
7
2
10
2.7
270%
1
=
50%
2
1
=
25%
4
3
=
75%
4
1
=
33.3%
3
2
=
66.6%
3
1
=
20%
5
2
=
40%
5
3
=
60%
5
4
=
80%
5
Percent shortcuts are very useful to
calculate percentages mentally.
They are fairly easy to do.
Please pay close attention as you
learn how to do this.
Find 17% of 300
10% of 300 = 30 300
5% of 300 = 15
300
1% of 300 = 3
3
1%
of
300
=
+
17% of 300 = 51
Lindsey was given lots of problems.
All of them required that she find
various percents of $200.
Lindsey made a table to help her
organize her data.
She used benchmarks to help her
solve each percent problem.
BENCHMARKS are common numbers
that serve as points of reference.
If you know your BENCHMARKS
then you can easily calculate harder
percent problems by combining
BENCHMARK numbers together.
Just watch!
1. What is 50% of 200? ____
100
50
2. What is 25% of 200? ___
20
3. What is 10% of 200? ____
4. What is 5% of 200? ____
10
2
5. What is 1% of 200? ____
12
1) 6% of 200 ______
6% = 5% + 1%
= 10 + 2
1. What is 50% of 200? ____
100
50
2. What is 25% of 200? ___
20
3. What is 10% of 200? ____
4. What is 5% of 200? ____
10
2
5. What is 1% of 200? ____
18
2) 9% of 200 ______
9% = 10% 1%
= 20 2
1. What is 50% of 200? ____
100
50
2. What is 25% of 200? ___
20
3. What is 10% of 200? ____
4. What is 5% of 200? ____
10
2
5. What is 1% of 200? ____
46
3) 23% of 200 ______
23% =
20% + 1% + 1% + 1%
or
25% 1% 1%
= 50 2 2
1. What is 50% of 200? ____
100
50
2. What is 25% of 200? ___
20
3. What is 10% of 200? ____
4. What is 5% of 200? ____
10
2
5. What is 1% of 200? ____
82
4) 41% of 200 ______
41% =
50% 10% + 1%
=100 20 + 2
Or.41% =
25% + 10% + 5% + 1%
Take out your
study guide
please.
#4
= 0.05 =
1
20
= 0.1
1
10
50% = 0.5
1
5
66.6%
25% = 0.25 =
1
4
5%
10%
20% = 0.2
33.3%
0.3
0.6
75% = 0.75 =
1
3
1
2
=
3
4
2
3
#5
1.
2.
3.
4.
5.
250
What is 50% of 500? ____
What is 25% of 500? ____
125
What is 10% of 500? ____
50
What is 5% of 500? ____
25
What is 1% of 500? ____
5
1) 8% of 500
8% = 10% 2%
= 50 10
= 40
2) 61% of 500
61% = 50% + 10% + 1%
= 250 + 50 + 5
= 305
#6
Estimate 21% of 66
21% 20% Use a benchmark close to 21%.
20% 1
66 65
1
5
Write 20% as a fraction.
Use compatible numbers.
65 = 13 Use mental math: 65 5.
So 21% of 66 is about 13.
Name___________
January 21, 2010
Period___
PERCENT SHORTCUTS (blue)
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