Education Technology

Probable Factors

Published on 07/11/2012

Activity Overview

What is the probability that a randomly generated quadratic will factorise? This investigation looks at a significantly reduced set of quadratics using dice to generate the coefficients. The coefficient of x is the sum of two dice and the constant is the product of two dice. Simulation is used for predicting the probability followed by theoretical computations.


  • Apply the distributive law to the expansion of algebraic expressions, including binomials, and collect like terms where appropriate (ACMNA213)
  • Expand binomial products and factorise monic quadratic expressions using a variety of strategies (ACMNA233)
  • Explore the connection between algebraic and graphical representations of relations such as simple quadratics, circles and exponentials using digital technology as appropriate (ACMNA239)
  • Describe the results of two- and three-step chance experiments, both with and without replacements, assign probabilities to outcomes and determine probabilities of events. Investigate the concept of independence (ACMSP246)


  • Quadratic Equations,
  • Distributivity,
  • Monomials,
  • Binomials,
  • Probability,
  • Experiments

About the Lesson

Students create a simulation using TI-nspire that produces four dice rolls simultaneously. The outcome from each is used to form a single quadratic equation. TI-nspire is then used to determine if the quadratic factorises, a simulation that is repeated by students to obtain an approximate answer to the questions "What is the probability that a randomly generated quadratic will factorise?" Students are then guided through a series of scaffolded questions to determine the theoretical probability.