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Grade 8:  The Learning Equation Math

12.10 Solve Ratio and Percent Problems

Number Operations

Refresher pp 30-31

Learning Outcomes:

The student will:

Percent Review

You can model percent with a 100 square grid.  Click on the individual pieces to add/subract pieces!!  Remember a percent (%) can be written as fraction with a denominator of 100.

 

Percent

23 : 100 = 23%

32/100 = 32%

a ratio whose second term is 100. Percent means "parts per hundred".   We use the symbol  /100 or  % for percent.
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Converting Fractions to Percent

3/4 = 75/100 = 75%

2/5 = 40/100 = 40%

3/10 = 30/100 = 30%

9/20 = 45/100 = 45%

use equivalent fractions, if the denominator is a factor of 100.

Algebra.help -- Fraction Simplifier

Converting Percent to Fractions

75% = 75/100 = 3/4

40% = 40/100 = 2/5

30% = 30/100 = 3/10

45% = 45/100 = 9/20

Change percent to a fraction with a denominatorof 100.   Reduce to lowest terms.

Quia - Matching - Percent - Fraction Match

 

Converting Fractions to Decimals

2/3 = 0.666...

15/9 = 1.555...

divide the numerator by the denominator if the denominator of the fraction is not a factor of 100.

Fraction - Decimal

Algebra.help -- Fraction Simplifier

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Converting Decimals to Fractions

0.84 = 84/100 = 21/25

1.43 = 1 43/100

Make sure there is at least two decimal places.  Move the decimal to the end of the hundredth digit and then place this number over 100.   Reduce to lowest terms.

If there are more than two decimal places, then move the decimal to the end of the last digit, then place the number over the following denominators:

3 decimal places --> /1000

4 decimal places --> /10 000

Quia - Matching - Fraction Decimal Conversion

0.333... = 3/9

0.666... = 6/9 = 2/3

1.555... = 1 5/9

For this course, the limit is single-digit nonterminating decimals.  The denominator for these fractions is 9.  Reduce to lowest terms.

Quia - Concentration - Fraction Decimal Conversion

Converting Decimals to Percent

0.005 = 0.5%

0.23 = 23%

0.67 = 67%

2.17 = 217%

3.456 = 345.6%

multiply the decimal by 100 to change the decimal to a percent.
Converting Percent to Decimals

0.5% = 0.005

23% = 0.23

67% = 0.67

217% = 2.17

345.6% = 3.456

divide the percent by 100 to change the percent to a decimal

QuickMath Automatic Math Solutions

Scientific Calculator

 

Review:

Percent Problem Types

What is  % of ? Answer:
 is what percent of ? Answer:  %
 is % of what? Answer:  %
source:  by Tom Richardson Jr.
http://home.rmci.net/gooftroop

Word problems involving percents

Enrichment:

 

Key Terms:

rate, ratio, proportion, percent

Wordsearch 12.06 - 12.11

Prerequisite Skills:

Percent:    Grade 7 Lesson 12.07

Three-Term Rations:  Grade 8 Lesson 1103.htm

Proportion:   Grade 7 Lesson 1209

 

 

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