IB Middle Years Programme · Mathematics (Extended) MYP Year 4

Graphs and Relations

Cover illustration for Graphs and Relations (Mathematics (Extended) MYP Year 4).
MYP · Mathematics (Extended) MYP Year 4

Graphs and Relations

MYP Mathematics Framework — Graphs and Relations (Year 5 Extended)

24 min readAdvancedCore strand of the Year 5 Extended course — assessed across Criteria A (Knowing/Understanding) and C (Communicating) in unit tests and the on-screen eAssessment; transformation and interpretation questions appear in almost every graphing paper.

This chapter is really three skills wearing one name: building a graph from an equation, reading a graph that's already drawn, and shifting a graph you already understand to describe a new situation. Examiners love the shift-and-read combination — give you , translate it, and ask what a specific point means in context (a drone's height, a sound level, a garden bed's depth). Get the sign conventions right and this whole topic becomes mechanical.

Overview — How This Topic Fits Together

What 'Graphs and Relations' actually tests

A relation links an input () to an output (). A function is a relation where every input gives exactly one output — that's the whole reason notation is safe to use. This chapter tests whether you can move between three representations of the same relationship: the equation, the table of values, and the graph — and translate between them without losing information (Q1 is built entirely around this trap).

  • Transformations describe how changing an equation moves, flips or stretches a graph — without needing to re-plot every point.
  • Real-life graphs need you to read gradient and area as physical quantities (rate of change, total distance), not just as lines on paper.
  • Linear, quadratic, cubic and exponential graphs each have a signature shape — recognising the shape from the equation (and vice versa) is non-negotiable at this level.
  • Parallel and perpendicular lines are just gradient rules dressed up in geometry language.

The shape of the chapter

Command terms this topic loves

Command termWhat it demandsAOMark-earning move
State / Write downGive the answer directly, no working requiredAO11 mark for the correct value alone — no method needed, but no credit if it's wrong even with correct-looking working nearby
CalculateObtain a numerical answer showing the working stepsAO2Method mark for correct substitution, answer mark for final value
DeduceReach a conclusion using given information or a previous result — not from scratchAO2/AO3Must explicitly link to the given data or earlier part; a bare correct answer with no link loses the reasoning mark
SketchDraw a graph showing general shape and key features (intercepts, vertex, asymptote) — not a precise plotAO2Marks for correct shape, correct intercept/vertex labels; axes must still be labelled
Interpret / ExplainConnect a mathematical feature to its real-world meaning in wordsAO3No marks for the number alone — the sentence explaining what it means in context is what's assessed
AnalyseBreak down a relationship and describe how the parts connect (e.g. how relates to )AO3Needs both the numerical pattern (add/subtract constant) and the graphical description (shift direction) for full marks

Key point

Every transformation rule secretly does the opposite of what it looks like inside the brackets: shifts the graph right, not left, and shifts it left. Outside the brackets, everything behaves normally: shifts up for positive .

Overview

Graphs and Relations — Lesson Notes | Mathematics (Extended) MYP Year 4