Cambridge Mathematics Online Courses
Lower Secondary
1.1 Whole Number Skills
1.2 Number Skills
1.3 Directed Numbers
1.4 Ratios
1.2 Number Skills
1.3 Directed Numbers
1.4 Ratios
2.1 Fractions
2.2 Decimals
2.3 Percentages
2.2 Decimals
2.3 Percentages
3.1 Algebraic Expressions
3.2 Number Sequences
3.3 Basic Equations
3.4 Linear Equations
3.5 Exponents
3.6 Straight Lines
3.7 Functions
3.8 Quadratic Equations
3.9 Simultaneous Equations
3.2 Number Sequences
3.3 Basic Equations
3.4 Linear Equations
3.5 Exponents
3.6 Straight Lines
3.7 Functions
3.8 Quadratic Equations
3.9 Simultaneous Equations
4.1 Angle Geometry
4.2 Transformations
4.3 Bearings
4.4 Pythagoras Theorem
4.5 Coordinate Geometry
4.2 Transformations
4.3 Bearings
4.4 Pythagoras Theorem
4.5 Coordinate Geometry
5.1 Angle Geometry
5.2 Time
5.3 Measurement
5.4 Perimeter
5.5 Area
5.6 Surface Area
5.7 Volume
5.2 Time
5.3 Measurement
5.4 Perimeter
5.5 Area
5.6 Surface Area
5.7 Volume
6.1 Presenting Data
6.2 Exploring Data
6.3 Linear Correlation
6.4 Probability
6.2 Exploring Data
6.3 Linear Correlation
6.4 Probability
7.1 Algebraic Expressions
7.2 Financial Mathematics
7.2 Financial Mathematics
IGCSE Core
1.1 Directed Numbers
1.2 Number Skills
1.3 Sets
1.4 Venn Diagrams
1.5 Fractions
1.6 Decimals
1.7 Percentages
1.8 Time
1.9 Measurement
1.A Interest Rates
1.B Ratios
1.C Rates
1.2 Number Skills
1.3 Sets
1.4 Venn Diagrams
1.5 Fractions
1.6 Decimals
1.7 Percentages
1.8 Time
1.9 Measurement
1.A Interest Rates
1.B Ratios
1.C Rates
2.1 Algebraic Expressions
2.2 Exponents
2.3 Linear Equations
2.4 Simultaneous Equations
2.5 Number Sequences
2.6 Quadratic Graphs
2.7 Kinematics
2.2 Exponents
2.3 Linear Equations
2.4 Simultaneous Equations
2.5 Number Sequences
2.6 Quadratic Graphs
2.7 Kinematics
3.1 Coordinate Geometry
3.2 Angle Geometry
3.3 Similarity
3.4 Congruence
3.5 Transformations
3.6 Circle Geometry
3.7 Measurement
3.8 Perimeter
3.9 Area
3.A Surface Area
3.B Volume
3.C Pythagoras Theorem
3.D Trigonometry
3.E Vectors
3.2 Angle Geometry
3.3 Similarity
3.4 Congruence
3.5 Transformations
3.6 Circle Geometry
3.7 Measurement
3.8 Perimeter
3.9 Area
3.A Surface Area
3.B Volume
3.C Pythagoras Theorem
3.D Trigonometry
3.E Vectors
4.1 Probability
4.2 Descriptive Statistics
4.3 Representing Data
4.4 Exploring Data
4.5 Linear Correlation
4.2 Descriptive Statistics
4.3 Representing Data
4.4 Exploring Data
4.5 Linear Correlation
IGCSE Extended
1.1 Directed Numbers
1.2 Number Skills
1.3 Sets
1.4 Venn Diagrams
1.5 Fractions
1.6 Decimals
1.7 Percentages
1.8 Time
1.9 Measurement
1.A Interest Rates
1.B Ratios
1.C Rates
1.D Growth and Decay
1.2 Number Skills
1.3 Sets
1.4 Venn Diagrams
1.5 Fractions
1.6 Decimals
1.7 Percentages
1.8 Time
1.9 Measurement
1.A Interest Rates
1.B Ratios
1.C Rates
1.D Growth and Decay
2.1 Algebraic Expressions
2.2 Factorisation
2.3 Exponents
2.4 Linear Equations
2.5 Simultaneous Equations
2.6 Number Sequences
2.7 Quadratic Equations
2.8 Quadratic Graphs
2.9 Functions
2.A Kinematics
2.B Cubic Polynomials
2.C Exponential Graphs
2.D Differentiation
2.2 Factorisation
2.3 Exponents
2.4 Linear Equations
2.5 Simultaneous Equations
2.6 Number Sequences
2.7 Quadratic Equations
2.8 Quadratic Graphs
2.9 Functions
2.A Kinematics
2.B Cubic Polynomials
2.C Exponential Graphs
2.D Differentiation
3.1 Coordinate Geometry
3.2 Angle Geometry
3.3 Similarity
3.4 Congruence
3.5 Transformations
3.6 Circle Geometry
3.7 Measurement
3.8 Perimeter
3.9 Area
3.A Surface Area
3.B Volume
3.C Pythagoras Theorem
3.D Trigonometry
3.E Trigonometric Graphs
3.F Non-Right Angled Triangles
3.G Vectors
3.2 Angle Geometry
3.3 Similarity
3.4 Congruence
3.5 Transformations
3.6 Circle Geometry
3.7 Measurement
3.8 Perimeter
3.9 Area
3.A Surface Area
3.B Volume
3.C Pythagoras Theorem
3.D Trigonometry
3.E Trigonometric Graphs
3.F Non-Right Angled Triangles
3.G Vectors
4.1 Probability
4.2 Descriptive Statistics
4.3 Representing Data
4.4 Exploring Data
4.5 Linear Correlation
4.2 Descriptive Statistics
4.3 Representing Data
4.4 Exploring Data
4.5 Linear Correlation
IGCSE Additional
1.1 Exponents
1.2 Surds
1.3 Polynomials
1.4 Coounting Techniques
1.5 Binomial Theorem
1.2 Surds
1.3 Polynomials
1.4 Coounting Techniques
1.5 Binomial Theorem
2.1 Quadratic Equations
2.2 Absolute Value Functions
2.3 Cubic Polynomials
2.4 Simultaneous Equations
2.5 Coordinate Geometry
2.2 Absolute Value Functions
2.3 Cubic Polynomials
2.4 Simultaneous Equations
2.5 Coordinate Geometry
3.1 Functions
3.2 Quadratic Functions
3.3 Exponential Graphs
3.4 Logarithms
3.5 Logarithmic Graphs
3.2 Quadratic Functions
3.3 Exponential Graphs
3.4 Logarithms
3.5 Logarithmic Graphs
4.1 Radian Measure
4.2 Trigonometric Graphs
4.3 Trigonometric identities
4.4 Trigonometric Equations
4.2 Trigonometric Graphs
4.3 Trigonometric identities
4.4 Trigonometric Equations
5.1 Vectors
5.2 Differentiation
5.3 Application of Differentiation
5.4 Differentiation of Trigonometric Functions
5.5 Integration
5.6 Application of Integration
5.2 Differentiation
5.3 Application of Differentiation
5.4 Differentiation of Trigonometric Functions
5.5 Integration
5.6 Application of Integration
IGCSE International Core
1.1 Number Skills
1.2 Ratios
1.3 Decimals
1.4 Fractions
1.5 Percentages
1.6 Interest Rates
1.7 Exponents
1.8 Measurement
1.9 Time
1.A Perimeter
1.B Area
1.C Surface Area
1.D Volume
1.2 Ratios
1.3 Decimals
1.4 Fractions
1.5 Percentages
1.6 Interest Rates
1.7 Exponents
1.8 Measurement
1.9 Time
1.A Perimeter
1.B Area
1.C Surface Area
1.D Volume
2.1 Algebraic Expressions
2.2 Linear Equations
2.3 Exponents
2.4 Simultaneous Equations
2.5 Factorisation
2.6 Algebraic Fractions
2.7 Number Sequences
2.2 Linear Equations
2.3 Exponents
2.4 Simultaneous Equations
2.5 Factorisation
2.6 Algebraic Fractions
2.7 Number Sequences
3.1 Functions
3.2 Transformations
3.3 Vectors
3.4 Set Theory
3.5 Venn Diagrams
3.2 Transformations
3.3 Vectors
3.4 Set Theory
3.5 Venn Diagrams
4.1 Coordinate Geometry
4.2 Angle Geometry
4.3 Similarity
4.4 Pythagoras Theorem
4.5 Circle Geometry
4.6 Trigonometry
4.2 Angle Geometry
4.3 Similarity
4.4 Pythagoras Theorem
4.5 Circle Geometry
4.6 Trigonometry
5.1 Descriptive Statistics
5.2 Probability
5.3 Representing Data
5.4 Exploring Data
5.5 Linear Correlation
5.2 Probability
5.3 Representing Data
5.4 Exploring Data
5.5 Linear Correlation
IGCSE International Extended
1.1 Number Skills
1.2 Ratios
1.3 Decimals
1.4 Fractions
1.5 Percentages
1.6 Interest Rates
1.7 Exponents
1.8 Surds
1.9 Measurement
1.A Time
1.B Perimeter
1.C Area
1.D Surface Area
1.E Volume
1.2 Ratios
1.3 Decimals
1.4 Fractions
1.5 Percentages
1.6 Interest Rates
1.7 Exponents
1.8 Surds
1.9 Measurement
1.A Time
1.B Perimeter
1.C Area
1.D Surface Area
1.E Volume
2.1 Algebraic Expressions
2.2 Linear Equations
2.3 Exponents
2.4 Simultaneous Equations
2.5 Factorisation
2.6 Algebraic Fractions
2.7 Quadratic Equations
2.8 Number Sequences
2.9 Linear Modelling
2.A Non-Linear Modelling
2.2 Linear Equations
2.3 Exponents
2.4 Simultaneous Equations
2.5 Factorisation
2.6 Algebraic Fractions
2.7 Quadratic Equations
2.8 Number Sequences
2.9 Linear Modelling
2.A Non-Linear Modelling
3.1 Functions
3.2 Quadratic Graphs
3.3 Transformations
3.4 Inverse Functions
3.5 Vectors
3.6 Set Theory
3.7 Venn Diagrams
3.2 Quadratic Graphs
3.3 Transformations
3.4 Inverse Functions
3.5 Vectors
3.6 Set Theory
3.7 Venn Diagrams
4.1 Coordinate Geometry
4.2 Angle Geometry
4.3 Similarity
4.4 Pythagoras Theorem
4.5 Circle Geometry
4.6 Trigonometry
4.7 Non-Right Angled Triangles
4.8 Trigonometric Graphs
4.2 Angle Geometry
4.3 Similarity
4.4 Pythagoras Theorem
4.5 Circle Geometry
4.6 Trigonometry
4.7 Non-Right Angled Triangles
4.8 Trigonometric Graphs
5.1 Descriptive Statistics
5.2 Probability
5.3 Representing Data
5.4 Exploring Data
5.5 Linear Correlation
5.2 Probability
5.3 Representing Data
5.4 Exploring Data
5.5 Linear Correlation
IGCSE (US) Core
1.1 Natural Numbers
1.2 Directed Numbers
1.3 Number Skills
1.4 Percentages
1.5 Ratios
1.6 Interest Rates
1.7 Exponents
1.8 Time
1.9 Measurement
1.A Radicals
1.2 Directed Numbers
1.3 Number Skills
1.4 Percentages
1.5 Ratios
1.6 Interest Rates
1.7 Exponents
1.8 Time
1.9 Measurement
1.A Radicals
2.1 Directed Numbers
2.2 Linear Equations
2.3 Exponents
2.4 Algebraic Expressions
2.5 Simultaneous Equations
2.6 Factorization
2.7 Number Sequences
2.2 Linear Equations
2.3 Exponents
2.4 Algebraic Expressions
2.5 Simultaneous Equations
2.6 Factorization
2.7 Number Sequences
3.1 Functions
3.2 Graphs
3.3 Exponential Graphs
3.4 Transformations
3.5 Vectors
3.6 Pythagoras Theorem
3.7 Trigonometry
3.2 Graphs
3.3 Exponential Graphs
3.4 Transformations
3.5 Vectors
3.6 Pythagoras Theorem
3.7 Trigonometry
4.1 Measurement
4.2 Angle Geometry
4.3 Circle Geometry
4.4 Perimeter
4.5 Area
4.6 Surface Area
4.7 Volume
4.8 Similarity
4.9 Coordinate Geometry
4.2 Angle Geometry
4.3 Circle Geometry
4.4 Perimeter
4.5 Area
4.6 Surface Area
4.7 Volume
4.8 Similarity
4.9 Coordinate Geometry
5.1 Probability
5.2 Descriptive Statistics
5.3 Representing Data
5.4 Exploring Data
5.5 Linear Modelling
5.2 Descriptive Statistics
5.3 Representing Data
5.4 Exploring Data
5.5 Linear Modelling
IGCSE (US) Extended
1.1 Natural Numbers
1.2 Directed Numbers
1.3 Number Skills
1.4 Percentages
1.5 Ratios
1.6 Interest Rates
1.7 Exponents
1.8 Time
1.9 Measurement
1.A Radicals
1.2 Directed Numbers
1.3 Number Skills
1.4 Percentages
1.5 Ratios
1.6 Interest Rates
1.7 Exponents
1.8 Time
1.9 Measurement
1.A Radicals
2.1 Directed Numbers
2.2 Linear Equations
2.3 Inequalities
2.4 Exponents
2.5 Algebraic Expressions
2.6 Simultaneous Equations
2.7 Factorization
2.8 Quadratic Equatoins
2.9 Number Sequences
2.A Non-Linear Modelling
2.2 Linear Equations
2.3 Inequalities
2.4 Exponents
2.5 Algebraic Expressions
2.6 Simultaneous Equations
2.7 Factorization
2.8 Quadratic Equatoins
2.9 Number Sequences
2.A Non-Linear Modelling
3.1 Functions
3.2 Graphs
3.3 Exponential Graphs
3.4 Trigonometric Graphs
3.5 Transformations
3.6 Inverse Functions
3.7 Vectors
3.8 Pythagoras Theorem
3.9 Trigonometry
3.A Non-Right Angled Triangles
3.2 Graphs
3.3 Exponential Graphs
3.4 Trigonometric Graphs
3.5 Transformations
3.6 Inverse Functions
3.7 Vectors
3.8 Pythagoras Theorem
3.9 Trigonometry
3.A Non-Right Angled Triangles
4.1 Measurement
4.2 Angle Geometry
4.3 Circle Geometry
4.4 Perimeter
4.5 Area
4.6 Surface Area
4.7 Volume
4.8 Similarity
4.9 Coordinate Geometry
4.2 Angle Geometry
4.3 Circle Geometry
4.4 Perimeter
4.5 Area
4.6 Surface Area
4.7 Volume
4.8 Similarity
4.9 Coordinate Geometry
5.1 Probability
5.2 Descriptive Statistics
5.3 Representing Data
5.4 Exploring Data
5.5 Linear Modelling
5.2 Descriptive Statistics
5.3 Representing Data
5.4 Exploring Data
5.5 Linear Modelling
IGCSE (US) Additional
1.1 Complex Numbers
1.2 Exponents
1.3 Radicals
1.4 Matrices
1.5 Polynomials
1.2 Exponents
1.3 Radicals
1.4 Matrices
1.5 Polynomials
2.1 Functions
2.2 Graphs
2.3 Exponential Functions
2.4 Logarithms
2.5 Logarithmic Graphs
2.2 Graphs
2.3 Exponential Functions
2.4 Logarithms
2.5 Logarithmic Graphs
3.1 Angle Geometry
3.2 Similarity
3.3 Coordinate Geometry
3.4 Graphs
3.5 Parabola
3.6 Conics
3.7 Radian Measure
3.8 Trigonometric Graphs
3.9 Trigonometric Identities
3.A Trigonometric Equations
3.2 Similarity
3.3 Coordinate Geometry
3.4 Graphs
3.5 Parabola
3.6 Conics
3.7 Radian Measure
3.8 Trigonometric Graphs
3.9 Trigonometric Identities
3.A Trigonometric Equations
4.1 Probability
4.2 Discrete Random Variables
4.3 Descriptive Statistics
4.4 Exploring Data
4.5 Normal Distribution
4.6 Representing Data
4.7 Linear Modelling
4.2 Discrete Random Variables
4.3 Descriptive Statistics
4.4 Exploring Data
4.5 Normal Distribution
4.6 Representing Data
4.7 Linear Modelling
O Level
1.1 Natural Numbers
1.2 Directed Numbers
1.3 Number Skills
1.4 Fractions
1.5 Decimals
1.6 Percentages
1.7 Ratios
1.2 Directed Numbers
1.3 Number Skills
1.4 Fractions
1.5 Decimals
1.6 Percentages
1.7 Ratios
2.1 Algebraic Expressions
2.2 Linear Equations
2.3 Factorisation
2.4 Exponents
2.5 Inequalities
2.6 Number Sequences
2.2 Linear Equations
2.3 Factorisation
2.4 Exponents
2.5 Inequalities
2.6 Number Sequences
3.1 Quadratic Graphs
3.2 Graphs
3.3 Functions
3.4 Non-Linear Modelling
3.5 Simultaneous Equations
3.6 Inequalities
3.7 Transformations
3.8 Matrices
3.2 Graphs
3.3 Functions
3.4 Non-Linear Modelling
3.5 Simultaneous Equations
3.6 Inequalities
3.7 Transformations
3.8 Matrices
4.1 Coordinate Geometry
4.2 Set Theory>br> 4.3 Venn Diagrams
4.4 Angle Geometry
4.5 Circle Geometry
4.6 Similarity
4.7 Locus
4.8 Pythagoras Theorem
4.9 Trigonometry
4.A Non-Right Angled Triangles
4.2 Set Theory>br> 4.3 Venn Diagrams
4.4 Angle Geometry
4.5 Circle Geometry
4.6 Similarity
4.7 Locus
4.8 Pythagoras Theorem
4.9 Trigonometry
4.A Non-Right Angled Triangles
5.1 Time
5.2 Spending Money
5.3 Interest Rates
5.4 Accuracy
5.5 Perimeter
5.6 Area
5.7 Surface Area
5.8 Volume
5.9 Vectors
5.2 Spending Money
5.3 Interest Rates
5.4 Accuracy
5.5 Perimeter
5.6 Area
5.7 Surface Area
5.8 Volume
5.9 Vectors
6.1 Probability
6.2 Descriptive Statistics
6.3 Representing Data
6.4 Exploring Data
6.5 Linear Modelling
6.2 Descriptive Statistics
6.3 Representing Data
6.4 Exploring Data
6.5 Linear Modelling
O Level Additional
1.1 Functions
1.2 Inverse Functions
1.3 Quadratic Functions
1.4 Exponential Graphs
1.5 Logarithms
1.6 Logarithmic Graphs
1.7 Coordinate Geometry
1.2 Inverse Functions
1.3 Quadratic Functions
1.4 Exponential Graphs
1.5 Logarithms
1.6 Logarithmic Graphs
1.7 Coordinate Geometry
2.1 Absolute Value Equations
2.2 Cubic Polynomials
2.3 Polynomials
2.4 Simultaneous Equations
2.5 Quadratic Equations
2.2 Cubic Polynomials
2.3 Polynomials
2.4 Simultaneous Equations
2.5 Quadratic Equations
3.1 Exponents
3.2 Surds
3.3 Counting Techniques
3.4 Binomial theorem
3.2 Surds
3.3 Counting Techniques
3.4 Binomial theorem
4.1 Radian Measure
4.2 Trigonometry
4.3 Trigonometric Graphs
4.4 Trigonometric Identities
4.5 Trigonometric Equations
4.6 Trigonometric Functions
4.2 Trigonometry
4.3 Trigonometric Graphs
4.4 Trigonometric Identities
4.5 Trigonometric Equations
4.6 Trigonometric Functions
5.1 Vectors
5.2 Vector Operations
5.3 Differentiation
5.4 Application of Differentiation
5.5 Integration
5.6 Exponential Functions
5.7 Logarithmic Functions
5.8 Application of Integration
5.2 Vector Operations
5.3 Differentiation
5.4 Application of Differentiation
5.5 Integration
5.6 Exponential Functions
5.7 Logarithmic Functions
5.8 Application of Integration
International AS and A Level
1.1 Quadratic Equations
1.2 Quadratic Inequalities
1.3 Quadratic Functions
1.4 Functions
1.5 Coordinate Geometry
1.6 Circles
1.7 Trigonometry
1.8 Binomial Theorem
1.9 Sequences and Series
1.A Differentiation
1.B Integration
1.2 Quadratic Inequalities
1.3 Quadratic Functions
1.4 Functions
1.5 Coordinate Geometry
1.6 Circles
1.7 Trigonometry
1.8 Binomial Theorem
1.9 Sequences and Series
1.A Differentiation
1.B Integration
2.1 Absolute Value Functions
2.2 Polynomials
2.3 Logarithms
2.4 Reciprocal Trigonometric Functions
2.5 Trigonometric Identities
2.6 Exponential Functions
2.7 Logarithmic Functions
2.8 Trigonometric Functions
2.9 Differentiation
2.A Numerical Approximation
2.2 Polynomials
2.3 Logarithms
2.4 Reciprocal Trigonometric Functions
2.5 Trigonometric Identities
2.6 Exponential Functions
2.7 Logarithmic Functions
2.8 Trigonometric Functions
2.9 Differentiation
2.A Numerical Approximation
3.1 Absolute Value Functions
3.2 Polynomials
3.3 Logarithms
3.4 Reciprocal Trigonometric Functions
3.5 Trigonometric Identites
3.6 Exponential Functions
3.7 Logarithmic Functions
3.8 Differentiation
3.9 Numerical Approximation
3.A Further Integration
3.B Vectors
3.C Differential Equations
3.D Complex Numbers
3.2 Polynomials
3.3 Logarithms
3.4 Reciprocal Trigonometric Functions
3.5 Trigonometric Identites
3.6 Exponential Functions
3.7 Logarithmic Functions
3.8 Differentiation
3.9 Numerical Approximation
3.A Further Integration
3.B Vectors
3.C Differential Equations
3.D Complex Numbers
4.1 Motions in Straight Lines
4.2 Constant Acceleration
4.3 Forces
4.4 Newton's Second Law
4.5 Vectors
4.6 Equilibrium and Resultant Forces
4.7 General Motions in Straight Lines
4.8 Friction Model
4.9 Work and Energy
4.2 Constant Acceleration
4.3 Forces
4.4 Newton's Second Law
4.5 Vectors
4.6 Equilibrium and Resultant Forces
4.7 General Motions in Straight Lines
4.8 Friction Model
4.9 Work and Energy
5.1 Descriptive Statistics
5.2 Representing Data
5.3 Exploring Data
5.4 Probability
5.5 Discrete Random Variables
5.6 Counting Techniques
5.7 Binomial Distribution
5.8 Normal Distribution
5.2 Representing Data
5.3 Exploring Data
5.4 Probability
5.5 Discrete Random Variables
5.6 Counting Techniques
5.7 Binomial Distribution
5.8 Normal Distribution
6.1 Hypothesis Testing
6.2 Poisson Distribution
6.3 Continuous Random Variables
6.4 Linear Combinations of Random Variables
6.2 Poisson Distribution
6.3 Continuous Random Variables
6.4 Linear Combinations of Random Variables
International AS and A Level Further
1.1 Matrices
1.2 Transformations using Matrices
1.3 Sequences and Series
1.4 Mathematical Induction
1.5 Quadratic Equations
1.6 Roots and Coefficients of Polynomials
1.7 Graphs
1.8 Vectors
1.2 Transformations using Matrices
1.3 Sequences and Series
1.4 Mathematical Induction
1.5 Quadratic Equations
1.6 Roots and Coefficients of Polynomials
1.7 Graphs
1.8 Vectors
2.1 Hyperbolic Functions
2.2 Matrices
2.3 Differentiation
2.4 Further Integration
2.5 Integration of Inverse Trigonometric Functions
2.6 Application of Integration
2.7 De Moivre's Theorem
2.8 Differential Equations
2.2 Matrices
2.3 Differentiation
2.4 Further Integration
2.5 Integration of Inverse Trigonometric Functions
2.6 Application of Integration
2.7 De Moivre's Theorem
2.8 Differential Equations
3.1 Projectile Motion
3.2 Moments of Forces
3.3 Centre of Mass
3.4 Circular Motion
3.5 Linear Motion under Variable Forces
3.2 Moments of Forces
3.3 Centre of Mass
3.4 Circular Motion
3.5 Linear Motion under Variable Forces
4.1 Continuous Random Variables
4.2 Inference using Normal and t-Distribution
4.3 Chi-Squared Distribution
4.4 Non-Parametric Tests
4.5 Probability Generating Functions
4.2 Inference using Normal and t-Distribution
4.3 Chi-Squared Distribution
4.4 Non-Parametric Tests
4.5 Probability Generating Functions