Comparing Quantities Using Ratios

Q3. W1. Ratios and comparing quantities

By Ms. Kim, Foundations for Algebra

SWBT compare quantities using subtraction and division

SWBT represent ratios and solve ratio problems

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Objectives

24 students with 6 computers in the classroom

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1. Subtraction : 24-6 =18

2.Division​: 24/6 = 4/1

​​Comparing two numbers

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There are 18 more students than computers (DiFference)

There are 4 students for every computer​ (Ratio)

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Multiple Choice

Which sentence accurately represents the following ratio:

• There are 4 moons for every 2 suns

• There are 4 moons for every 4 suns

1. Ratio: The comparison of two quantities using division

2. Written Expression

​-fraction

-Colon (:)

- Read as: ____ to ____

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Ratio

Multiple Choice

Express as a fraction

• $$\frac{1}{45}$$  

• $$\frac{2}{85}$$  

• $$\frac{85}{2}$$  

Multiple Choice

Patrick has 2 black, 3 red, and 5 white toy cars.

What is the ratio of red toy cars to all the toy cars?

• 3:5

• 2:3

• 3:10

Percent: A ratio that compares a number to 100 (rati0 x100)

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PART to PART

PART TO WHOLE​

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Types of ratio / comparison

Multiple Choice

To compare two numbers

a part to part (girl: boy = 5:15)

What is

a part to whole (boy: whole)

• 15:20

• 5:20

• 5:15

Unit: Ratio is a quantity that usually has units with same kinds

​ ex) 3 dogs to 4 cats

cf: Rate: units with different kinds​

ex) 500miles per hour​

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​Ratio Unit

Multiple Choice

What does that mean?

• 55miles/hour

• 45miles/second

• 55miles/minute

Number of orange / Number of apple

Ratio: 2 : 5

Fraction: 2/5

-Word: two oranges for every five apples

- The number of oranges is 40% of the number of apples. 0.4 x100 =40% ​

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Ratio-comparison-percent

​1. A part to part: 2:3

2. A part to whole : 2 : 5 or 3 : 5​

Multiple Choice

How do you convert to ratio to percent?

Choose all

• The simplest ratio-> decimal->

  x 100

• ratio x 100

• 3/2 ->

  1.5 ->

  1.5x100 = 150%

12 girls and 8 boys

-N of girls/n of all students: 12/20

-The simplest form of 12/20: 3/5

- The simplest whole number: 3 : 5

-Replace this with your body text.

​Duplicate this text as many times as you would like.

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Ratio-decimal- percent

Multiple Choice

1. Ratio as dog to whole animals

_____

2. Percent of dog of total animals

--------- %

Order: Simplest Ratio - decimal- x100

• 2:8

  50%

• 2:8

  25%

• 6:8

  35%