3.1 Small Group · Group 2
Tier 1 Extension · Non-Routine Synthesis · Misconception Traps · Rigorous CER Proofs
Understand Ratios · Ratio · Procedural Fluency · Real-World Applications
- You already can do this. So we go up a level, not up a number: find what is always true, show it a second way, and be ready to defend it with a reason instead of an answer.
- Chef Reyes uses 3 cups of apple juice for every 2 cups of sparkling water.
- I am comparing two amounts: apple juice and sparkling water.
- I write apple juice to sparkling water, in that order, as 3 to 2, or 3:2.
- I can also draw the ratio. On a tape diagram I give apple juice 3 equal parts and sparkling water 2 equal parts, so one batch is 5 parts in all.
- Those same 5 parts show a second ratio: apple juice to the whole fruit drink is 3 to 5.
- On a double number line I line the two amounts up: 5 cups of fruit drink pairs with 3 cups of apple juice, and 10 cups of fruit drink pairs with 6 cups of apple juice.
- A bowl has 4 apples and 1 orange. What two amounts are we comparing?
- We write apples to oranges in order: 4 to 1, or 4:1.
- Now draw it: 4 equal parts for apples beside 1 part for oranges, 5 parts of fruit in all.
- So apples to total fruit is 4 to 5.
- Now prove it: say why that move had to work at all — not just that it did.
- Sentence frame — convince a skeptic: "My method works because ___ . It would stop working if ___ ."
- Understand Ratios (Comprender razones) — Use a ratio to compare two quantities by division.
- Ratio (Razón) — A way to compare two amounts, like 3 to 2.
- Comparison (Comparación) — Looking at two or more amounts to see how they are related.
- Part-to-part (Parte a parte) — A ratio comparing one part of a group to another part.
- Part-to-whole (Parte a todo) — A ratio comparing one part to the whole group.
- Colon notation (Notación con dos puntos) — Writing a ratio with two dots between the numbers, like 3:2.
- A common mistake in Understand Ratios is writing the ratio in the wrong order: when asked for the ratio of apple juice to sparkling water in a recipe that uses 3 cups of apple juice for every 2 cups of sparkling water, some students write 2:3 (sparkling water to apple juice) because they list the ingredients in whatever order comes to mind rather than the order the question asks for. The two ratios describe different drinks — 3:2 means 3 cups of juice for every 2 cups of water, while 2:3 would mean only 2 cups of juice for every 3 cups of water. Always match the order of your ratio to the order named in the question: "apple juice to sparkling water" means the apple juice number comes first, giving 3:2.
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1 DRAG SORT
Sort each statement — is it a part-to-part ratio or a part-to-whole ratio?
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2 FILL TABLE
Complete the table by writing each ratio in all three forms.
Description Word Form Colon Form Fraction Form 4 cats to 7 dogs 9 red out of 15 total 5 wins to 3 losses ✏️ Scratchpad / Reasoning
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3 MULTIPLE CHOICE
Prep Bowl A: Chef Reyes stirs 7 cups of flour with 4 cups of water to make dough. What is the part-to-part ratio of flour to water?
- A7:4
- B4:7
- C7:11
- D11:4
✏️ Workspace & Solution Steps -
4 MULTIPLE CHOICE
A class has 5 chefs and 7 helpers (12 total). What is the part-to-whole ratio of chefs to the whole class?
- A5:12
- B5:7
- C7:12
- D12:5
✏️ Workspace & Solution Steps -
5 MULTIPLE CHOICE
“For every” language: Chef Reyes says, “My glaze uses 9 spoons of honey for every 4 spoons of lemon.” Written in colon notation, the ratio of honey to lemon is:
- A9:4
- B4:9
- C9:13
- D13:4
✏️ Workspace & Solution Steps
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6 OPEN RESPONSE
A bag of marbles has 8 red, 6 blue, and 4 green marbles. Write three different ratios using these quantities: one part-to-part ratio, one part-to-whole ratio, and explain the difference.
✏️ Mathematical Justification & Response
Group Discussion Prompt: How does your visual model justify your mathematical solution?
Partner A: "I modeled this by identifying the relationship and..."
Partner B: "I agree with your step because the standard mathematical rule states..."
Complete each sentence stem to demonstrate precise mathematical reasoning:
Writing Task: Justify why your mathematical solution is accurate and complete.