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Math · 9th Grade
Function Notation
f(x) is not multiplication — and everything else follows from getting that right.
How to use it
Read f(3) as 'f of 3', never 'f times 3'. The habit prevents a year of errors.
Free · print-ready PDF · US Letter and A4
- Grade
- 9th Grade
- Ages
- 14–15
- Subject
- Math
- Pages
- 1
The rest of the 9th Grade wall
49 more posters, all free to print.
Domain and RangeWhich inputs are allowed, and which outputs actually appear.Factoring Out the GCFThe first thing to try, every single time, before anything else.Factoring TrinomialsTwo numbers that multiply to c and add to b — and what to do when a is not 1.Difference of SquaresThe pattern worth spotting instantly, and the one that looks similar but does not factor.The Quadratic FormulaThe method that always works, and the sign errors that ruin it.The DiscriminantOne calculation that tells you how many solutions there are before you find them.Anatomy of a ParabolaVertex, axis, roots and direction — everything a quadratic graph tells you.Choosing a Systems MethodGraphing, substitution or elimination — decided by the shape of the equations.Arithmetic SequencesAdd the same amount each time — and the formula that jumps straight to any term.Proving Triangles CongruentFive shortcuts that work, and the two that look like they should but do not.Triangle TheoremsSix rules that solve most triangle questions without measuring anything.Writing a Geometry ProofThe structure, and the habit that makes proofs writable rather than mysterious.Similar TrianglesSame shape, different size — and the scale factor rules for length, area and volume.Cell TheoryThree statements that underpin the whole of biology.DNA StructureA twisted ladder, and the base pairing that makes copying possible.From Gene to ProteinTranscription then translation — two steps, two locations.Photosynthesis and RespirationTwo equations that are almost exact mirrors of each other.Punnett SquaresPredicting offspring ratios from two parents' genes.Evidence for EvolutionFive independent lines of evidence, all pointing the same way.EnzymesBiological catalysts, and the two things that destroy them.HomeostasisKeeping the inside steady while the outside changes.Function ToolkitDomain, range, notation and the parent functions with their graphs.QuadraticsFactoring, the quadratic formula, the discriminant and parabola anatomy.Systems of EquationsGraphing, substitution and elimination side by side, plus what 'no solution' looks like.Geometry ReferenceAngle relationships, triangle rules, congruence shortcuts and the proof vocabulary.Literary TermsThe terms high-school essays are expected to use, grouped and defined.Thesis & EvidenceHow to build a defensible thesis and the evidence sandwich that supports it.Cell Structure & FunctionEvery organelle with its job, plus transport across the membrane.Periodic TrendsAtomic radius, ionisation energy and electronegativity, with arrows for each trend.Exponential FunctionsGrowth that multiplies rather than adds — and why it always wins eventually.Solving and Graphing InequalitiesThe same steps as an equation, with one rule and one extra piece of notation.Absolute Value EquationsOne equation, two cases — because distance works in both directions.Adding and Multiplying PolynomialsCombine like terms to add; distribute everything to multiply.Levels of Ecological OrganisationFrom one organism up to the whole biosphere.The Carbon CycleWhere carbon goes, and where humans changed the balance.Making a Scientific ClaimClaim, evidence, reasoning — the structure every lab conclusion needs.Close ReadingFour passes over a text, each looking for something different.Analysing Sentence StructureWhat sentence length and shape do to a reader.Rhetorical Devices in SpeechesSix techniques that turn up in almost every famous speech.Graphing a Line FastFour points plotted in under thirty seconds, from any form.Rearranging FormulasSolving for a letter when everything else is letters too.Simplifying RadicalsPulling perfect squares out from under the root sign.Viruses and Living ThingsWhy virology sits awkwardly between chemistry and biology.The Nitrogen CycleWhy the most abundant gas in the air is useless to almost everything.CharacterisationDirect and indirect — and why writers prefer the second.Symbol, Motif and ThemeThree connected ideas, and how one builds into the next.Evaluating Research SourcesFive checks before a source goes into a bibliography.From Notes to EssayThe bridge between having read everything and having written nothing.Managing a Long AssignmentWorking backwards from the deadline, and the two hardest days.
