Algebra I
Grades 8 to 128 units and 60 lessons. Helio talks each one through and draws each step on a board.
Units
Relationships between quantities
5 lessons- Units as a guide: unit analysis and scalesConvert quantities and rates, check formula units, and compare graph rates using labelled scales.
- Defining quantities and choosing a sensible level of accuracyDefine quantities with units, choose relevant information, and report answers at a sensible precision.
- Interpreting the parts of an expressionInterpret an expression’s signed terms, factors, coefficients, and quantities, including a repeated growth factor.
- Using structure to write equivalent expressionsRewrite expressions using their structure and justify why the new forms have the same value.
- Exponent rules, radicals and rational exponents; sums and products of rational and irrational numbersSimplify expressions with exponents and radicals, then justify whether exact results are rational or irrational.
Linear equations and inequalities
10 lessons- Solving as reasoning: justifying each stepSolve linear equations, justify each line, and check solutions in the original equation.
- Solving multistep linear equations, including special casesSolve multistep equations and distinguish one solution, no solution, and every real number as a solution.
- Writing equations and inequalities in one variable from situationsDefine an unknown, write a relationship from a situation, solve it, and interpret the answer.
- Rearranging formulas to highlight a quantityRearrange a formula to leave a requested variable alone, including when it appears in two terms.
- Solving and graphing linear inequalities, including compound inequalitiesSolve and graph single and compound inequalities, including reversing signs when dividing by a negative.
- Absolute value equations and inequalitiesSolve absolute value equations and inequalities, graph solutions, and check candidates in the original statement.
- Slope from two points, tables and graphsFind the slope of a line from two points, a table or a graph, and say what it means as a rate with units.
- Slope-intercept form: graphing and writing linesGraph a line from y = mx + b, write y = mx + b from a graph, a point and slope, or two points, and say what m and b mean in a story.
- Point-slope and standard form; converting between forms; horizontal and vertical linesWrite a line in point-slope form from one point and a slope, graph from standard form using intercepts, convert between all three forms, and choose the form the information suggests.
- Equations in two variables and modelling with constraintsWrite a two-variable equation, graph its intercepts, and identify pairs that meet every constraint.
Systems of equations
5 lessons- Systems of linear equations: solutions as intersectionsFind and check a shared point, then predict how many solutions two lines have.
- Solving systems by substitutionSolve a system by substitution, check its ordered pair, and recognize no solution or infinitely many solutions.
- Solving systems by elimination, and why it worksSolve systems by elimination and explain why scaling and reversible combinations preserve their solutions.
- Modelling with systems and choosing a methodModel two facts with a system, choose a solution method, and check the answer in context.
- Systems of a linear and a quadratic equationFind and check every point shared by a line and a parabola; use the same substitution idea with a circle.
Graphs of equations and inequalities
3 lessons- The graph of an equation is the set of all its solutionsDecide whether a point belongs on an equation’s graph and explain why the graph contains more than table points.
- Solving f(x) = g(x) by graphing: intersections, tables and successive approximationFind every input where two graphs meet, and approximate inputs that fall between gridlines.
- Graphing linear inequalities and systems of inequalities as half-planesGraph each inequality and identify the points that satisfy every rule in a system.
Functions
10 lessons- What a function is: one output per input, function notation, domain and rangeTest whether a relation is a function, read function notation, and find domain and range in context.
- Sequences as functions: arithmetic and geometric, recursive and explicitIdentify a constant difference or ratio, write rules with the correct start, and find a specified term.
- Interpreting key features of graphs and tables in contextInterpret graph and table features with input and output units, then sketch a graph from a story.
- Average rate of change over an intervalFind and interpret average rates from graphs, tables, and formulas, with appropriate units.
- Graphing linear, quadratic, square root, cube root, absolute value, piecewise and step functionsSketch each family from a rule, labeling anchor points, key features and included endpoints.
- Equivalent forms that reveal properties: zeros, vertex, growth and decay ratesChoose a form to find a quadratic’s zeros, vertex, or y-intercept, and read an exponential rate per stated time unit.
- Comparing functions given in different representationsCompare the same property of two functions, even when one is an equation and the other is a table or graph.
- Building functions from contexts and combining standard functionsBuild functions from a situation, combine them, and use the result to answer a question.
- Transforming graphs: f(x) + k, k·f(x), f(kx), f(x + k), and even and odd functionsDescribe graph shifts and scales, find a multiplier from a point, and classify functions as even, odd, or neither.
- Inverse functions for linear functionsFind a linear function’s inverse, check it by a round trip, and identify its graph points.
Linear and exponential models
6 lessons- Equal differences or equal factors: telling linear from exponentialClassify tables and situations by comparing changes over equal input intervals.
- Writing linear and exponential functions from graphs, tables, descriptions and two pointsWrite and check a linear or exponential rule from a graph, table, description or two points.
- Exponential growth eventually overtakes linear and quadratic growthCompare models with tables and growing steps to find when an exponential takes a lasting lead.
- Interpreting the parameters of linear and exponential models in contextInterpret each model number with its units, its meaning, and the context’s starting time.
- Graphing exponential functions: intercept, asymptote, growth and decaySketch y = a·bˣ from a table, name its y-intercept and asymptote, tell growth from decay by b, and say its domain and range.
- Percent growth and decay; simple and compound interestWrite a growth or decay model from a percent rate, tell simple interest from compound interest, use A = P(1 + r/n)^(nt), and estimate a doubling time.
Quadratic expressions and equations
13 lessons- Adding, subtracting and multiplying polynomialsAdd, subtract and multiply polynomials; use special products and identify a product’s degree.
- Factoring out the GCF and factoring x^2 + bx + cFactor a quadratic completely by taking out the greatest common factor, then finding the pair with the right product and sum, and read the zeros from the factors.
- Factoring ax^2 + bx + c by groupingFactor a trinomial whose x² term has a coefficient by splitting the middle term with the product ac, grouping, and checking by multiplying back.
- Special products: difference of squares and perfect square trinomialsSpot a difference of squares or a perfect square trinomial, factor it without a search, and factor completely when a common factor or a repeated pattern is hiding.
- Solving quadratic equations by factoringSolve a quadratic equation by making one side zero, factoring, and checking every solution.
- Solving quadratics by inspection and square rootsSolve by isolating a squared expression, finding all real solutions, and simplifying exact roots.
- Completing the square to reveal the vertex and solveRewrite a quadratic to find its vertex, then complete the square to solve an equation.
- The quadratic formula and the discriminantSolve quadratics with the formula and predict the number of real solutions from the discriminant.
- Choosing a method to solve a quadraticChoose an efficient method, solve exactly when possible, and check which solutions fit the question.
- Graphing quadratic functions: vertex, axis of symmetry and interceptsSketch a parabola from its opening, axis, vertex, intercepts and mirror points, and say what its minimum or maximum value is.
- Vertex form and maximum/minimum problemsRead the vertex from y = a(x − h)² + k, rewrite a quadratic into that form, and use it to find the best input and the best value in a situation.
- Projectile motion and other quadratic modelsRead a launch model h(t) = −16t² + v₀t + h₀, then find its peak, its landing time and the times it reaches a target height, keeping only answers that fit the story.
- Using properties of exponents to rewrite exponential expressionsRewrite an exponential model for a new time unit and interpret its growth rate.
Describing data
8 lessons- Dot plots, histograms and box plots on the real number lineDraw three displays on an even number line and choose one to answer a data question.
- Comparing center and spread: median, mean, IQR and standard deviationCompare two groups using a center and a matching spread, with values and units.
- Shape, skew and outliers: how they move the center and spreadName a distribution’s shape, test for outliers with IQR fences, and choose a useful center and spread.
- Two-way tables, relative frequencies and associationCalculate relative frequencies, judge association, and distinguish association from cause.
- Scatter plots and fitting linear, quadratic and exponential modelsPlot paired data, choose a model from its pattern, and judge whether a prediction is within the data range.
- Residuals and residual plots: judging how well a model fitsCalculate residuals, plot them against x, and use their pattern to judge a model’s fit.
- Interpreting slope and intercept of a linear model in contextInterpret a fitted line’s slope and intercept with units and predicted language; decide whether its intercept is meaningful.
- Correlation coefficient and correlation versus causationInterpret r, recognize its limits, and explain why correlation alone does not establish causation.
