lesson 7 __attachment_a

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?