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Straight Lines and Connected Representations · Lesson 01 — A line as a relationship

NEO Mathematics: Straight Lines

A line as a relationship

Driving Question: Can a line tell the same story as an equation, a table and a graph?

Lesson type: Connected representations — one linear relationship seen five ways.

Stepping Stone: connect linear representations — move between a story, a table, coordinates, an equation and a graph of the same line.

NEO Cornerstones: Connection · Movement · Reflection · Creativity · Rest · Nutrition

45-minute shape: Connect 15 · Move 8 · Reflect 10 · Create 5 · Rest/Nourish 4 · Evidence 3

📚 Lesson Support, Reconnection and Scratchpad

Choose only the support that helps now. Every route returns you to this lesson.

🌱 Open Learner Guide 📘 Open Supporting Adult Guidance

🎬 Watch first — the story behind the grid

Every graph in this unit sits on a grid of coordinates: a way of pairing numbers with position on a page. That idea was shaped by the philosopher and mathematician René Descartes (1596–1650) — which is why we call it the Cartesian plane. Here is his story, in about three minutes.

Captions are on their way. If you would rather skip the film, that is completely fine — scroll on to begin.

🌿 Connection — One line, five costumes

🔤 New words for this lesson

Linear relationship — a relationship whose graph is a straight line: equal steps in x give equal steps in y.
Representation — a way of showing the relationship: in words, a table, coordinates, an equation, or a graph.
Equation y = mx + c — the line's rule: c is the y-intercept (the value of y when x = 0), and m is the step — how much y changes each time x goes up by 1.

What to do: drag the m and c sliders and watch all five representations change together — the story, the table, the coordinates, the equation and the graph.

What you are trying to notice: these are not five different things — they are five costumes on one relationship. Change the line and every view updates at once.

📈 One Line, Five Costumes

Graph & coordinates

Equation
Story

Table

Carry this forward: a straight line is one relationship in five costumes. Everything else in this unit is a closer look at its two numbers — m and c.

🚶 Movement — Step the story along the line

What to do: press Next step to move along the line one x at a time. Watch the dot climb the same amount at every step, and the running total grow.

What you are trying to notice: the line is a constant step — each time x goes up by 1, y goes up by the same amount, m. That steady step is what makes it straight.

👣 Step the Story

Carry this forward: equal steps in x give equal steps in y. That equal step has a name you will meet soon: the gradient.

🪞 Reflection — Match the representation

What to do: each card shows a line in one costume — a table or a story. Choose the equation that matches it, then check.

What you are trying to notice: you can move from any one representation to another by finding the two numbers: where it starts (c) and how much it steps (m).

🧩 Which equation is it?

Carry this forward: to match representations, read off the start and the step — that is c and m, the whole of y = mx + c.

🎨 Creativity — Model a real story

What to do: pick a real situation, then set the m and c sliders so the line tells its story. Check how close you are.

What you are trying to notice: a straight line can model a real situation — the starting amount is c and the steady change is m.

✏️ Model the Story

Make it your own: on the Scratchpad, invent your own straight-line story and sketch its graph, table and equation.

🌙 Rest — A pause to let it settle

Holding one relationship in five forms at once asks a lot of your attention. Take a breath before moving on.

Notice one thing: which costume of a line feels most natural to you — the story, the table, the equation or the graph? There is no right answer — just what your own attention noticed.

You can jot it on the Scratchpad, say it aloud, or simply hold it in mind. You can pause here and return whenever you are ready.

🍎 Nutrition — Where does this show up in the real world?

Mode: contextual. Straight-line relationships are everywhere a fixed amount meets a steady rate.

Why it matters: a phone tariff (a monthly fee plus a cost per gigabyte), a taxi fare (a flag price plus a rate per mile), wages (a bonus plus an hourly rate), a savings plan, a currency conversion — each is a line with an intercept c (the fixed amount, when x = 0) and a steady rate m. People read these lines every day to compare deals and predict costs. Being able to move between the story, the numbers and the graph is what lets you choose well.

Next time you see a "fixed fee plus a rate", picture the line — what is its fixed amount (c), and how steep is it (m)?

🛠️ Final Task — Evidence for today

Your task: show one line in five costumes.

  • Choose or invent a straight-line situation (for example "£4 to join, then £2 each visit"). Show it as a story, a table, a set of coordinates, an equation and a graph.
  • Explain, in your own words, how the story's starting value and steady step appear in the equation y = mx + c.
  • Change one number in your story and describe how all five representations change with it.

Submission choices: an annotated Scratchpad image, a written solution, a labelled poster, or a spoken/video walkthrough.

Filename pattern: NEO_MATH_SL_A_LINE_AS_A_RELATIONSHIP_FirstName_Date

CriterionApproaching ProficiencyDeveloping ProficiencyProficiencyRefining Proficiency
UnderstandingKnows a line can be shown as a graph and an equation.Links two representations with support.Shows one relationship in several representations.Moves fluently between all five and states the shared relationship.
ApplicationReads a value from a graph or table.Builds a table from a rule with prompting.Generates a table, coordinates and graph from an equation.Translates confidently in any direction, including from a story.
CommunicationRecords a representation with limited labelling.Labels a table or graph.Sets out each representation clearly.Explains so another learner could rebuild the line.
ReflectionNames one thing noticed.Spots that the views describe one line.Explains how c and m show up across representations.Connects representations to real linear situations.

✏️ Ready to strengthen your understanding?