9.2 Small Group · Group 2
Tier 1 Extension · Non-Routine Synthesis · Misconception Traps · Rigorous CER Proofs
graph · table of values · 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.
- Each ticket costs $45, so the total cost is 45 times the number of tickets: 1 ticket is $45, 2 tickets are $90, 3 tickets are $135.
- The number of tickets is the independent variable, so it goes first in each ordered pair: (1, 45), (2, 90), (3, 135).
- I label one axis 'Number of tickets' and the other 'Total cost ($)', then plot each pair as a point.
- The points rise to the right: as the number of tickets increases, the total cost increases.
- The tram travels 1,200 feet every minute. Which quantity is independent — time or distance?
- Time is independent, so our pairs look like (minutes, feet): (1, 1200), (2, 2400), (5, 6000).
- The ascent takes 15 minutes, so the last point is (15, 18000) — because 15 times 1,200 is 18,000 feet.
- Each point means: after THIS many minutes, the tram has traveled THIS many feet.
- 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 ___ ."
- graph (gráfica) — A picture on a coordinate plane that shows how two quantities are related.
- table of values (tabla de valores) — A list of matched pairs of values that shows a relationship using numbers.
- ordered pair (par ordenado) — Two numbers written as (x, y) that name one point on a graph. The independent variable comes first.
- axis (eje) — One of the two number lines that frame a graph. Each axis is labeled with a quantity from the problem.
- coordinates (coordenadas) — The numbers in an ordered pair that tell how far to move along each axis to reach a point.
- Reversing the coordinates of a point — writing (cost, tickets) instead of (tickets, cost). The independent variable always comes first in the ordered pair.
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1 MULTIPLE CHOICE
The ticket table and ticket graph are two representations. Which statement about them is true?
- ABoth show the same relationship — the table with numerical values, the graph in a more visual way
- BThe graph shows a different relationship than the table
- COnly the table can show that cost increases with tickets
- DOnly the graph is a real mathematical representation
✏️ Workspace & Solution Steps
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2 COORDINATE GRID
Plot the ticket-cost relationship: one point for each number of tickets.
✏️ Workspace & Solution Steps
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3 MULTIPLE CHOICE
Nakai earns $26.25 in simple interest every year. On the graph of years vs. interest earned, which point represents 4 years?
- A(4, 105)
- B(4, 26.25)
- C(4, 78.75)
- D(4, 750)
✏️ Workspace & Solution Steps -
4 MULTIPLE CHOICE
After 10 minutes, the Sandia Peak tram has traveled 12,000 feet. The whole ascent is 18,000 feet. How much farther must it travel to reach the top?
- A6,000 feet
- B12,000 feet
- C5,000 feet
- D1,200 feet
✏️ Workspace & Solution Steps -
5 MULTIPLE CHOICE
A second tram travels 900 feet per minute. If both trams are graphed on the same axes (minutes vs. feet), how do the graphs compare?
- AThe Sandia Peak line (1,200 ft/min) rises more steeply than the 900 ft/min line
- BThe 900 ft/min line rises more steeply
- CThe two lines are identical
- DThe 900 ft/min line goes downward
✏️ Workspace & Solution Steps
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6 OPEN RESPONSE
The ticket graph has “Number of tickets” across the bottom and “Total cost ($)” up the side. Rowan plots the first ticket as the point (45, 1). What did Rowan misunderstand — and what does his point actually claim about tickets and money?
✏️ Mathematical Justification & Response
Complete each sentence stem to demonstrate precise mathematical reasoning:
Writing Task: Justify why your mathematical solution is accurate and complete.