lesson 7 __attachment_a
TRANSCRIPT
PercentsPercents
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What is a percent?What is a percent? A percent is a ratio…how many times out A percent is a ratio…how many times out
of a hunderedof a hundered
45 %
= 45100
45 percent means 45 out of
100 possible times!
This means that all This means that all percentages can be percentages can be
written as a fraction by written as a fraction by simply placing them over simply placing them over
100.100.
Write these percents as fractionsWrite these percents as fractions
1)1) 30 %30 %
2)2) 40 %40 %
3)3) 12 %12 %
4)4) 99 %99 %
5)5) 101 %101 %
3/103/10
2/52/5
3/253/25
99/10099/100
1 1/1001 1/100
Dude…That was
cool
How can you turn a percent into a
fraction?
What are the most steps that could be
involved?
If I can write any percent If I can write any percent as a fraction over a as a fraction over a
hundred, then how can I hundred, then how can I write any percent as a write any percent as a
decimal?decimal?
That’s RightThat’s Right
Since I can put all percents over a Since I can put all percents over a hundred then all I need to do is write hundred then all I need to do is write the equivalent decimal. (Remember the equivalent decimal. (Remember they sound the same.)they sound the same.)
20 % =20
100= 0.20
You try…Percent to DecimalYou try…Percent to Decimal
6)6) 12 %12 %
7)7) 8 %8 %
8)8) 75 %75 %
9)9) 48 %48 %
10)10)120 %120 %
0.120.12
0.080.08
0.750.75
0.480.48
1.201.20
How can you turn a percent into a
decimal?
How are percents related to How are percents related to decimals and fractions?decimals and fractions?
And if they all represent the And if they all represent the same amounts then we can same amounts then we can turn any fraction, decimal, or turn any fraction, decimal, or percent into the other.percent into the other.
If you were given a fraction, then set If you were given a fraction, then set up a proportionality. You know the up a proportionality. You know the fraction, and you know that all fraction, and you know that all percents are over 100. The fraction percents are over 100. The fraction and the percent must be equivalent.and the percent must be equivalent.
5
40=
P
100
40 · P = 5 · 100
40P = 500
500
40
= 12.5 %
Your turn…Your turn…
11)11)4/1004/100
12)12)2/52/5
13)13)3/43/4
14)14)2/32/3
15)15)2 1/22 1/2
4 %4 %
40 %40 %
75 %75 %
66.6 %66.6 %
250 %250 %
How can you turn a fraction into a
percent?
What are the most steps that could be
involved?
For DecimalsFor DecimalsRewrite your decimal as a Rewrite your decimal as a
fraction. fraction. Remember they sound exactly Remember they sound exactly
the same.the same. If your denominator is 100, then If your denominator is 100, then
write your percent.write your percent. If not, then make your proportion If not, then make your proportion
and solve.and solve.
0.43 =100
43
0.3 =3
10=
P
100
10P = 300
300
10
P = 30 %
= 43 %
Your turn…Your turn…
16)16) 0.240.24
17)17) 0.050.05
18)18) 0.140.14
19)19) 0.70.7
20)20) 1.481.48
24 %24 %
5 %5 %
14 %14 %
70 %70 %
148 %148 %
Dude…That was Awesome
How can you turn a decimal into a
percent?
What are the most steps that could be
involved?