unit 2, lesson 2: representing ratios with...

Unit 2, Lesson 2: Representing Ratios with Diagrams

2.1: Number Talk: Dividing by 4 and Multiplying by (10 minutes)

Setup: Display one problem at a time. 1 minute of quiet think time, followed by a whole-class discussion.

Lesson GoalsPractice using the following language: The ratio of these to those is . The ratio ofthese to those is to . For every of these, there are of those.Write different ratios to represent the same situation.Draw discrete diagrams to represent situations involving ratios.

Required Materialscopies of blackline mastercolored pencilstools for creating a visual displaypre-printed slips, cut from copies ofthe blackline master

Student task statementFind the value of each expression mentally.

Possible responses

1. 6

2. 6

3. 6

4. or equivalent

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GRADE 6 MATHEMATICS

Open Up Resources(openupresources.org)

Unit 2: Introducing Ratios, Lesson 2: Representing Ratios with Diagrams 1

2.2: A Collection of Snap Cubes (Optional, 10 minutes)

Setup: Students in groups of 2. Access to colored pencils.

Student task statementHere is a collection of snap cubes.

2. Trade papers with a partner. On their paper, write a sentence to describe a ratio shown in their diagram.Your partner will do the same for your diagram.

3. Return your partner’s paper. Read the sentence written on your paper. If you disagree, explain yourthinking.

1. Choose two of the colors in the image, and draw adiagram showing the number of snap cubes forthese two colors.

Possible responses

Answers vary.

Anticipated misconceptions

Students might not draw discretediagrams at first. They might be inclinedto draw more detailed drawings.Emphasize that a diagram representsthe number and type of objects, anddoes not need to represent detailsabout the shapes of the snap cubes.

GRADE 6 MATHEMATICS



2.3: Blue Paint and Art Paste (10 minutes)

Setup: Students in groups of 2. Provide tools for creating a visual display.

GRADE 6 MATHEMATICS



Student task statementElena mixed 2 cups of white paint with 6 tablespoons of blue paint.

1. Discuss the statements that follow, and circle all those that correctly describe this situation. Make surethat both you and your partner agree with each circled answer.

A. The ratio of cups of white paint to tablespoons of blue paint is .

B. For every cup of white paint, there are 2 tablespoons of blue paint.

C. There is 1 cup of white paint for every 3 tablespoons of blue paint.

D. There are 3 tablespoons of blue paint for every cup of white paint.

E. For each tablespoon of blue paint, there are 3 cups of white paint.

F. For every 6 tablespoons of blue paint, there are 2 cups of white paint.

G. The ratio of tablespoons of blue paint to cups of white paint is 6 to 2.

2. Jada mixed 8 cups of flour with 2 pints of water to make paste for an art project.

a. Draw a diagram that represents the situation.

Here is a diagram thatrepresents this situation.

Possible responses

1. A, C, D, F, G

2. Diagrams and statements vary. Theratio of cups of flour to pints ofwater is .


Some students may think all of thestatements about the paint mixture areaccurate descriptions. If so, suggestthat there are two false statements.Have students discuss the statementsagain in determining which two arefalse.

GRADE 6 MATHEMATICS



b. Write at least two sentences describing the ratio of flour and water.

GRADE 6 MATHEMATICS



2.4: Card Sort: Spaghetti Sauce (15 minutes)

Setup:

Students in groups of 2. Place two copies of uncut blackline masters in envelopes to serve as answer keys. Demonstrate the protocol forthe activity. Give each group cut-up cards for matching.

GRADE 6 MATHEMATICS



Student task statement

1. Take turns with your partner to match a sentence with a diagram.

a. For each match that you find, explain to your partner how you know it’s a match.

b. For each match that your partner finds, listen carefully to their explanation. If you disagree, discussyour thinking and work to reach an agreement.

2. After you and your partner have agreed on all of the matches, check your answers with the answer key. Ifthere are any errors, discuss why and revise your matches.

3. There were two diagrams that each matched with two different sentences. Which were they?

Diagram _______ matched with both sentences ______ and ______.

Diagram _______ matched with both sentences ______ and ______.

4. Select one of the other diagrams and invent another sentence that could describe the ratio shown in thediagram.

Your teacher will give you cards describing different recipes forspaghetti sauce. In the diagrams:

a circle represents a cup of tomato saucea square represents a tablespoon of oila triangle represents a teaspoon of oregano

Possible responses

1. The blackline master shows thecorrect matching.

2. No answer necessary.

3. a. Diagram B matches withsentences 2 and 8.

b. Diagram E matches withsentences 3 and 7.

4. Answers vary.


If students disagree about a match,encourage them to figure out thecorrect answer through discussion anduse of the answer key. Make sure thatwhen students use the answer key, theydiscuss any errors rather than justmake changes.

Students may think the shapes in thediagram need to be drawn in the same

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GRADE 6 MATHEMATICS



Lesson Synthesis (5 minutes)What are some good things to remember when you draw a diagram of a ratio? How can a diagram help you make sense of a situationinvolving a ratio?

2.5: Paws, Ears, and Tails (Cool-down, 5 minutes)

Setup: None.

order the ingredients appear in thedescription. This is not the case. Youcould turn a diagram card upside downand it would still represent the samesituation. The diagram just showsingredients that get mixed together in apot. It is the case, however, that withinthe description, the order of the wordsin the sentence must correspond withthe terms within the ratio.

Are you ready for more?Create a diagram that represents any of the ratios in a recipe of your choice. Is it possible to include more than2 ingredients in your diagram?

Possible Responses

Answers vary.

GRADE 6 MATHEMATICS



Student task statementThere are 3 cats in a room and no other creatures. Each cat has 2 ears, 4 paws, and 1 tail.

1. Draw a diagram that shows an association between numbers of ears, paws, and tails in the room.

2. Complete each statement:

a. The ratio of ______________ to ______________ to ______________ is ______ : _______ : ______.

b. There are ______ paws for every tail.

c. There are ______ paws for every ear.

Possible responses

1. Diagrams vary.

2. The ratio of ears to paws to tails is.

3. There are 4 paws for every tail.

4. There are 2 paws for every ear.


In the second question, students maynot realize that the order of the wordsin the sentence must correspond withthe terms within the ratio. Ears : paws :tails must correspond with . Inthe fourth question, students may notwrite the sentence for every one ear. Ifthis is the case, prompt them to draw acircle around each set of two paws andone ear to help them see thisrelationship.

GRADE 6 MATHEMATICS



unit 2, lesson 2: representing ratios with...

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