6.AT.3 Group 2 · Challenge

Practice Set · Part 1

Compare Ratio Relationships

Pick up where we left off

Name: Date: Group:

Where we left off

Our goal: I can compare ratios by finding unit rates or using equivalent ratios, explain how I can tell, and judge a case I have not seen before.

The big idea: Compare ratios fairly by making one part equal or by finding the unit rate — and you can say why it is true, and where it would stop being true.

Model to copy — Watch me

  1. Chef Reyes uses 3 tbsp cocoa for 5 oz milk (3:5). Chef Tran uses 4 tbsp for 7 oz milk (4:7).
  2. I cannot compare yet because the milk amounts are different.
  3. I scale both to 35 oz of milk. For Reyes: 5 x 7 = 35, so 3 x 7 = 21 tbsp, giving 21:35.
  4. For Tran: 7 x 5 = 35, so 4 x 5 = 20 tbsp, giving 20:35.
  5. Now the milk is equal, so I compare cocoa: 21 > 20, so Chef Reyes's cocoa is more chocolatey.

Start here

You did these with your group. Now do them on your own — the model above is yours to copy.

  1. 1

    Same stepsFinish what the group started. Use the model above, step for step.

    Try it together — then prove it: Store A sells 2 pens for $6. Store B sells 3 pens for $12. Which is the better deal? Find each unit rate, the price for 1 pen. Store A: 6 divided by 2 = $3 per pen. Store B: 12 divided by 3 = $4 per pen. Store A is cheaper at $3 per pen. Now prove it: say why that move had to work at all — not just that it did.
    Show your work
  2. 2

    Warm restartA ratio table for 3:2 gives the points (3, 2) and (6, 4). Which point also lies on the same graph?

    1. A(9, 6)
    2. B(9, 5)
    3. C(8, 6)
    4. D(2, 3)

    How do you know?

  3. 3

    Warm restartThe graph of a set of equivalent ratios always passes through which point?

    1. A(0, 0)
    2. B(1, 1)
    3. C(1, 0)
    4. D(0, 1)

    How do you know?

  4. 4

    Warm restartOn a graph of cups of juice (x) to cups of water (y), the point (4, 10) is plotted. What ratio does that point show?

    1. A4:10
    2. B10:4
    3. C4:14
    4. D14:10

    How do you know?

3.5 Small Group · Group 2 · Practice SetPart 1 of 4
6.AT.3 Group 2 · Challenge

Practice Set · Part 2

Compare Ratio Relationships

Keep going

You answered these out loud. Now write them.

Answer, then say how you know — the reason is the part that counts.

  1. 5

    Think it throughWhat is Mario's price per pizza?

    1. A$9.00
    2. B$18.00
    3. C$8.33
    4. D$4.50

    Why is that the answer?

  2. 6

    Think it throughWhat is Sal's price per pizza?

    1. Aabout $8.33
    2. Babout $12.50
    3. Cabout $9.00
    4. Dabout $7.50

    How do you know? Give a second reason as well.

  3. 7

    Think it throughWhich shop is the better deal?

    1. ASal's, because $8.33 per pizza is less than $9.00
    2. BMario's, because $18 is less than $25
    3. CMario's, because 2 is less than 3
    4. DThey cost the same

    Explain your thinking. What would have to change for a different choice to be right?

  4. 8

    Back to the modelThe two recipes use different amounts, so you cannot compare them directly. How did building equivalent ratios let you compare them fairly?

3.5 Small Group · Group 2 · Practice SetPart 2 of 4
6.AT.3 Group 2 · Challenge

Practice Set · Part 3

Compare Ratio Relationships

Words and reasoning

Word bank · Banco de palabras

Compare Ratios (Comparar razones)Unit rate (Tasa unitaria)Equivalent ratio (Razón equivalente)Compare (Comparar)Simplify (Simplificar)Common denominator (Denominador común)

Use the words

Fill each blank with a word from the bank.

Explain the thinking

  1. 9

    Find the mistakeAnother student made this exact mistake in this lesson. Explain why it is wrong, then write what they should have done.

    The mistake: A common mistake in Compare Ratios is thinking the ratio with the bigger raw number automatically wins — like assuming Chef Tran's 8 tablespoons of cocoa must be more chocolatey than Chef Reyes's 6 tablespoons, without checking that the milk amounts (14 oz vs.
  2. 10

    Say moreYou scaled both recipes to 35 oz of milk: Chef Reyes became 21:35 and Chef Tran became 20:35. How does scaling to a common denominator let you compare the recipes fairly?

  3. 11

    Write your ownWrite your own problem about this situation, then solve it and show the answer. The situation: Two chefs each mixed cocoa and milk to make the cups of hot cocoa shown. Each used a different ratio of cocoa to milk.

    Show your work
3.5 Small Group · Group 2 · Practice SetPart 3 of 4
6.AT.3 Group 2 · Challenge

Practice Set · Part 4

Compare Ratio Relationships

Show what you know

Last check

These two come from Lesson 3.4. If they are shaky, that is the lesson to revisit — not this one.

  1. 12

    Show what you knowExplain your thinking — A bakery sells 4 muffins for $10 and another bakery sells 6 muffins for $14. Which bakery has the lower price per muffin?

    1. AThe second bakery
    2. BThe first bakery
    3. CSame price
    4. DCannot determine

    Explain your choice.

  2. 13

    From Lesson 3.4Explain your thinking — A ratio table shows cups of rice to cups of water: (1, 2), (2, 4), (3, 6). If you plot these points, the line passes through which point?

    1. A(5, 10)
    2. B(4, 6)
    3. C(5, 8)
    4. D(6, 10)

    How do you know?

  3. 14

    From Lesson 3.4Which point would NOT be on this line?

    1. A(4, 8)
    2. B(10, 20)
    3. C(6, 12)
    4. D(5, 12)

    How do you know?

Be honest — this tells your teacher what to do next

I can…Not yetGetting thereGot it
I can compare ratios by finding unit rates or using equivalent ratios, explain how I can tell, and judge a case I have not seen before.
I can explain why it works: Compare ratios fairly by making one part equal or by finding the unit rate — and you can say why it is true…
I can justify my answer to a skeptic and connect it to a second strategy or representation.

One question I want to ask my group next time